Article

Zoysiagrass Species and Genotypes Differ in Their Winter Injury and Freeze Tolerance

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Abstract

Lack of cold hardiness may limit widespread use of newly released zoysiagrass (Zoysia spp.) cultivars in the transition zone. Our objectives were to quantify differences in the winter injury of 35 zoysiagrass genotypes in fi eld plots in West Lafayette, IN, and the freeze tolerance of 13 genotypes in a cold stress simulator as well as determine the relationship between leaf width, establishment rate, and autumn growth with winter injury. Winter injury varied between years and among genotypes in the fi eld study. Zoysia japonica Steud. genotypes had less win- ter injury each year than Z. matrella (L.) Merr. genotypes. Genotypes of Z. japonica available as seed had less winter injury (2% in both years) than genotypes of Z. japonica (41%, 2005; 54%, 2006) and Z. matrella (51%, 2005; 73%, 2006) available only as vegetative propagules. 'Meyer', 'Chinese Common', and 'Zenith' were the commercially available cultivars exhibit- ing the least winter injury (88%) both years. There was a relationship (r2 = 0.48, P = 0.0088) between freeze tolerance (LT50) in the cold stress simulator and winter injury in the fi eld. Freeze tolerance ranged from −8.4°C (Dia- mond) to −11.5°C (Meyer and Zenith). Meyer has been the industry standard for zoysiagrass, but our research has identifi ed other commercially available cultivars and genotypes with winter injury similar to Meyer.

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... Therefore, artificial freezing tests with a controlled cooling rate have been successfully conducted in the past in a controlled environment to evaluate the freeze tolerance of turfgrasses. Most artificial freezing studies determine the lethal temperatures to kill 50% of the population (LT 50 ) based on the whole-plant regrowth following exposure to freezing temperatures (Anderson et al., 1993(Anderson et al., , 2002Dunne et al., 2019;Kimball et al., 2017;Patton and Reicher, 2007;Qian et al., 2001;Shahba et al., 2003). Thus, the objective of this study was to determine the LT 50 values of experimental and commercially available putting green hybrid bermudagrass genotypes by subjecting them to 11 freezing temperatures ranging from -4 to -14°C, under controlled environment conditions. ...
... The experiment was conducted at the OSU Controlled Environment Research Laboratory at Stillwater, OK. The freezing protocol was performed in accordance with previously conducted studies with slight modifications (Anderson et al., 1993(Anderson et al., , 2002Patton and Reicher, 2007). The study was conducted in three batches, due to space constraints in the plant growth chamber and the freeze chamber. ...
... Watering was stopped 2 d before loading samples into the freeze chamber. The cone-tainers were randomized in the freeze chamber within temperature treatments (Patton and Reicher, 2007). Ten thermocouple sensors, logged into the control panel of the freeze chamber, were inserted into random cone-tainers to monitor the soil temperature. ...
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The susceptibility of warm-season turfgrasses such as bermudagrass ( Cynodon spp.) to winter injury in the transition zone is a major concern. Therefore, the objective of the study was to evaluate five golf course putting green-type experimental genotypes (OKC6318, OKC0805, OKC1609, OKC0920, and OKC3920) and three commercially available bermudagrasses (‘Champion Dwarf’, ‘TifEagle’, and ‘Tahoma 31’) for freeze tolerance by subjecting them to 11 freezing temperatures (–4 to –14 °C) under controlled environment conditions. The experiment was conducted in batches, with four genotypes per batch, and each batch was replicated in time. The mean lethal temperature to kill 50% of the population (LT 50 ) for each genotype was determined. There were significant differences in LT 50 values among the bermudagrass genotypes. ‘Champion Dwarf’ had an LT 50 value ranging from –5.2 to –5.9 °C across all three batches. The experimental genotypes tested in this study had LT 50 values ranging from –7.0 to –8.1 °C and were each lower than that of ‘Champion Dwarf’. ‘Tahoma 31’, the top performing genotype, had an LT 50 value ranging from –7.8 to –9.0 °C across all three batches. OKC 3920 was the only experimental genotype with an LT 50 value in the same statistical group as ‘Tahoma 31’. The information gained from this research would be useful for breeders to gauge the genetic gain in freeze tolerance in breeding golf course putting green-type bermudagrass.
... Zoysiagrasses (Zoysia spp.) are warm-season, allotetraploid (2n = 4x = 40) turfgrasses used for their low growth habit, density, fine texture, and general tolerance to drought, shade and salinity and suitable for golf and sports turf, home and commercial lawn use (Li et al. 2009;Patton et al. 2017). Zoysia species, particularly Z. japonica, are known to have the highest levels of freezing tolerance of the warm-season grasses, but their lack of winter hardiness and freezing tolerance in comparison to cool-season grasses limits its use north of the transitional climatic zone (Patton and Reicher, 2007). As evidenced by the current most freezing tolerant cultivar 'Meyer', which was released in 1951 (Grau and Radko, 1951), limited progress has been made through traditional breeding methods to increase the level of freezing tolerance in the species. ...
... As evidenced by the current most freezing tolerant cultivar 'Meyer', which was released in 1951 (Grau and Radko, 1951), limited progress has been made through traditional breeding methods to increase the level of freezing tolerance in the species. Only two Z. japonica cultivars, 'Chinese Common' and 'Zenith' have been determined to have comparable winter hardiness to Meyer (Patton and Reicher, 2007), so there is ample room for improvement to broaden the pool of winter hardy and freezing tolerant cultivars in order to expand the commercial range of zoysiagrass farther north. ...
... Cold acclimation, defined as exposure to low, non-freezing temperatures plays a crucial role in increasing freezing tolerance (Guy, 1990). The physiological components of winter hardiness and cold acclimation in zoysiagrass have also been examined (Rogers et al. 1975;Dunn et al. 1999;Patton and Reicher, 2007;Hinton et al. 2012;Holloway et al. 2018), but little progress has been achieved in identifying the genetic components of the trait. Recently, Brown et al. (2020) reported that cold acclimation accounted for a 1.9-fold increase in zoysiagrass survival compared to the non-acclimation treatment in a controlled environment freezing test. ...
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Zoysiagrasses (Zoysia spp.) are relatively low‐input and warm‐season turfgrasses which have grown in popularity in the United States since their introduction in the 1890's. Over thirty improved zoysiagrass cultivars were released in the past three decades, but many lack freezing tolerance and their use is limited to warm‐humid climates. Understanding the genetic controls of winter hardiness and freezing tolerance in zoysiagrass could considerably benefit the breeding efforts to increase tolerance to freezing stress. In the present study, controlled environment acclimation and freezing tests were utilized to evaluate a Meyer x Victoria zoysiagrass mapping population for post‐freezing surviving green tissue (SGT) and regrowth (RG). Quantitative trait loci (QTL) mapping analysis identified nine QTL associated with SGT, eight QTL linked to RG, and 22 QTL common in both traits, accounting for between 6.4 and 12.2% of the phenotypic variation. Eleven regions of interest overlapped with putative winter injury QTL identified in a previous field study. Upon sequence analysis, homologs of several abiotic response genes were found underlying these overlapping QTL regions. The homologs of these gene encode transcription factors, cell wall modification related proteins, and defense signal transduction related proteins. Following further validation, these QTL and their associated markers have potential to be utilized in future breeding efforts for the development of a broader pool of zoysiagrass cultivars capable of surviving in cold climates. This article is protected by copyright. All rights reserved
... The two most popular species of zoysiagrass in the United States, Z. japonica and Z. matrella (L.) Merr., have significantly different levels of winter injury and spring green-up as first reported by Forbes and Ferguson (Forbes & Ferguson, 1947). In both field and freeze chamber studies, Z. japonica genotypes show more average freeze tolerance than Z. matrella genotypes (Dunn, Bughrara, Warmund, & Fresenburg, 1999;Hinton, Livingston, Grady, Peacock, & Tuong, 2012;Patton & Reicher, 2007). Patton and Reicher (2007) reported that the temperature at which the sample has a 50% mortality (LT 50 ) for Z. japonica commercial cultivars range from −9.5 to −11.5 • C for Victoria and Meyer, respectively. ...
... In both field and freeze chamber studies, Z. japonica genotypes show more average freeze tolerance than Z. matrella genotypes (Dunn, Bughrara, Warmund, & Fresenburg, 1999;Hinton, Livingston, Grady, Peacock, & Tuong, 2012;Patton & Reicher, 2007). Patton and Reicher (2007) reported that the temperature at which the sample has a 50% mortality (LT 50 ) for Z. japonica commercial cultivars range from −9.5 to −11.5 • C for Victoria and Meyer, respectively. Additionally, LT 50 values have been found to differ depending on the origin of the tested material and freeze testing protocol (Dunn et al., 1999;Hinton et al., 2012;Patton & Reicher, 2007;Zhang, Fry, Rajashekar, Bremer, & Engelke, 2009). ...
... Patton and Reicher (2007) reported that the temperature at which the sample has a 50% mortality (LT 50 ) for Z. japonica commercial cultivars range from −9.5 to −11.5 • C for Victoria and Meyer, respectively. Additionally, LT 50 values have been found to differ depending on the origin of the tested material and freeze testing protocol (Dunn et al., 1999;Hinton et al., 2012;Patton & Reicher, 2007;Zhang, Fry, Rajashekar, Bremer, & Engelke, 2009). ...
Article
Zoysiagrasses (Zoysia spp.) are warm season turfgrasses primarily grown in the southern and transition zones of the United States. An understanding of the physiological and proteomic changes that zoysiagrasses undergo during cold acclimation may shed light on phenotypic traits and proteins useful in selection of freeze tolerant genotypes. We investigated the relationship between cold acclimation, protein expression, and freeze tolerance in cold‐acclimated (CA) and non‐acclimated (NCA) plants of Zoysia japonica Steud. cultivars ‘Meyer’ (freeze‐tolerant) and ‘Victoria’ (freeze‐susceptible). Meristematic tissues from the grass crowns were harvested for proteomic analysis. Freeze testing indicated that cold acclimation accounted for a 1.9‐fold increase in plant survival compared to the non‐acclimation treatment. Overall, proteomic analysis identified 62 protein spots differentially accumulated in abundance under cold acclimation. Nine and 22 unique protein spots were identified for Meyer and Victoria, respectively, with increased abundance or decreased abundance. In addition, 23 shared protein spots were found among the two cultivars in response to cold acclimation. Function classification revealed that these proteins were involved primarily in transcription, signal transduction and stress defense, carbohydrate and energy metabolism, protein and amino acid metabolism. Several proteins of interest for their association with cold acclimation were identified. Further investigation of these proteins and their functional categories may contribute to increase our understanding of the differences in freezing tolerance among zoysiagrass germplasm. This article is protected by copyright. All rights reserved
... Zoysiagrass (Zoysia spp.) is one of the most widely used warm-season turfgrasses in home lawns, athletic fields and parks because of its good performance to high temperature, water deficit, traffic tolerance and low maintenance [23,29]. The optimum temperature for the growth and development of zoysiagrass is from 25˚C to 30˚C. ...
... In eastern China, their natural distribution covers from latitude 19˚03 0 N to 41˚02 0 N and from longitude 1090 3 0 E to124˚04 0 E [32]. Among all the warm-season turfgrasses, however, zoysiagrass is the most tolerant species in freezing tolerance than other ones, but the cold injuries during the winter season vary widely among zoysiagrass species and genotypes [29]. Our preliminary investigation in a field study showed that zoysiagrass native to high latitude exhibit great freezing tolerance than the ones native to low latitude. ...
... Temperature may be the main environmental factor determining the natural latitudinal and altitudinal distribution of plants. The native distribution of zoysiagrass in China extends diverse latitude covers from 19˚03 0 N to 41˚02 0 N [32], which showed greater freezing tolerance than other warm-season turfgrasses and vary cold tolerance among zoysiagrass species and genotypes [29]. Two representative genotypes were chosen for this study based on our preliminary investigation in a field study, which demonstrated that the genotype native to higher Effect of low temperature on the total chlorophyll content in two zoysiagrass genotypes native to diverse latitude. ...
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Low temperature is one of the important limiting factors for growing season and geographical distribution of plants. Zoysiagrass (Zoysia Willd) is one of the widely used warm-season turfgrass that is distribute in many parts of the world. Zoysaigrass native to high latitude may have evolved higher cold tolerance than the ones native to low latitude. The objective of this study was to investigate the cold stress response in zoysiagrass native to diverse latitude at phenotypic, physiological and metabolic levels. Two zoysiagrass (Z. japonica) genotypes, Latitude-40 (higher latitude) and Latitude-22 (lower latitude) were subjected to four temperature treatments (optimum, 30/25°C, day/night; suboptimum, 18/12°C; chilling, 8/2°C; freezing, 2/-4°C) progressively in growth chambers. Low temperature (chilling and freezing) increased leaf electrolyte leakage (EL) and reduced plant growth, turf quality, chlorophyll (Chl) content, photochemical efficiency (Fv/Fm) and photosynthesis (Pn, net photosynthetic rate; gs, stomatal conductance; intercellular CO2; Tr, transpiration rate) in two genotypes, with more rapid changes in Latitude-22. Leaf carbohydrates content (glucose, fructose, sucrose, trehalose, fructan, starch) increased with the decreasing of temperature, to a great extend in Latitude-40. Leaf abscisic acid (ABA), salicylic acid (SA) and jasmonic acid (JA) content increased, while indole-3-acetic acid (IAA), gibberellic acid (GA3) and trans-zeatin ribside (t-ZR) content decreased with the reduction of temperature, with higher content in Latitude-40 than in Latitude-22. Chilling and freezing induced the up-regulation of C-repeat binding factor (ZjCBF), late embryogenesis abundant (ZjLEA3) and dehydration-responsive element binding (ZjDREB1) transcription factors in two genotypes, whereas those genes exhibited higher expression levels in Latitude-40, particularly under freezing temperature. These results suggested that zoysiagrass native to higher latitude exhibited higher freezing tolerance may attribute to the higher carbohydrates serving as energy reserves and stress protectants that stabilize cellular membranes. The phytohormones may serve signals in regulating plant growth, development and adaptation to low temperature as well as inducing the up-regulated ZjCBF, ZjLEA3 and ZjDREB1 expressions thus result in a higher cold tolerance.
... The release of the remarkably freeze-tolerant cultivar Meyer in 1951, increased zoysiagrass' use and popularity in the transition zone (Grau and Radko 1951;Patton et al. 2017). New cold-tolerant cultivars BChinese Common^and BZenith^have comparable winter hardiness to Meyer, (Patton and Reicher 2007), but improvements over this cultivar have not been released to date. ...
... Quantitative trait loci have been identified for salt tolerance (Guo et al. 2014) and fall armyworm resistance (Jessup et al. 2011;Huang et al. 2016). Although physiological components of winter hardiness in zoysiagrass are well-researched (Rogers et al. 1975;Dunn et al. 1999;Hinton et al. 2012;Patton and Reicher 2007), attempts at genetic dissection of the trait through the use of molecular tools are few. ...
... japonica) at the North Carolina State University greenhouses (Raleigh, NC). These parents were chosen based on reported lethal temperatures (LT 50 s) (Patton and Reicher 2007). From these crosses, a pseudo-F 2 mapping population of 175 individuals was developed and propagated in 7.6 × 7.6 × 7.6 cm plastic pots (Hummert International, Earth City, MO), filled with Fafard 4P potting mix (Conrad Fafard Inc., Agawam, MA) and allowed to completely fill the container. ...
Article
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Zoysia japonica Steud. (2n = 4× = 40) is a C4 turfgrass well-adapted for the warm-humid and transitional climatic zones of the USA. Its use is limited to warmer climates because of a relative lack of winter hardiness compared to C3 grasses. Molecular markers associated with this trait would be useful for effective selection of winter hardy germplasm before field testing. A pseudo-F2 mapping population of 175 individuals was developed from crosses between Z. japonica cultivars “Meyer” (freeze-tolerant) and “Victoria” (freeze-susceptible) and used to generate a high-density genetic map of 104 SSR markers and 2359 sequencing-derived SNP markers. The map covers 324 Mbp and 2520 cM as well as the 20 chromosomes for the zoysiagrass haploid genome. Phenotypic data on winter injury, establishment, and turf quality collected in North Carolina and Indiana in 2014–2016 were used in conjunction with this map to identify quantitative trait loci (QTL) associated with winter hardiness. Fifty-six QTL associated with winter injury, establishment, and turf quality were identified over six environments. Twelve of those were identified in two or more environments. Furthermore, seven regions of interest were identified on chromosomes 8, 11, and 13 where co-location of QTL for three or more traits occurred. Within these regions, analysis with NCBI basic local alignment search tool (BLAST) identified proteins related to cold and other abiotic stresses tolerance. These QTL and associated markers could be valuable in implementing marker-assisted selection for winter hardiness in zoysiagrass breeding programs.
... These adaptive differences often dictate the use and distribution of species in the United States. Cold hardiness is variable, with Z. japonica > Z. matrella > Z. pacifica (Forbes, 1952;Patton and Reicher, 2007). Zoysia matrella has slightly better shade tolerance than Z. japonica, but this is highly cultivar dependent (Riffell et al., 1995;Trappe et al., 2011d;Wherley et al., 2011). ...
... Similar to growth rate, cold hardiness of zoysiagrass is both a strength and a shortcoming. As mentioned previously, cold hardiness is variable among Zoysia spp., with a ranking by species of Z. japonica > Z. matrella > Z. pacifica (Forbes, 1952;Patton and Reicher, 2007). This ranking is predictable considering the centers of origin for these species: Z. japonica is native to Korea and Japan (temperate climate), Z. matrella is native to a broad geography in Asia (both temperate and tropical climates), and Z. pacifica is native to the Pacific islands (tropical climate) (Engelke and Anderson, 2003;Tanaka et al., 2016b). ...
... This ranking is predictable considering the centers of origin for these species: Z. japonica is native to Korea and Japan (temperate climate), Z. matrella is native to a broad geography in Asia (both temperate and tropical climates), and Z. pacifica is native to the Pacific islands (tropical climate) (Engelke and Anderson, 2003;Tanaka et al., 2016b). Although Z. japonica has better cold hardiness than other Zoysia species, Patton and Reicher (2007) found large differences in response to freezing temperatures and winter injury between cultivars. Only select cultivars are recommended in locations whose climate offers severe winter stress Fig. 6). ...
Article
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Since its introduction into the United States in 1892, zoysiagrass (Zoysia spp. Willd.) has made a tremendous impact on the US turfgrass industry. Three species of zoysiagrass [Z. japonica Steud., Z. matrella (L.) Merr., and Z. pacifica (Goudswaard) M. Hotta & S. Kuroki] collected from East Asia and the Pacific Islands were introduced into the United States and are used directly as turf or by turfgrass breeders in the development of advanced lines. Golf courses, lawns, grounds, sod farms, athletic fields, roadsides, and airports are some of the many locations where zoysiagrass is used. While almost 50 improved cultivars of zoysiagrass have been developed to date, active efforts to improve zoysiagrass further and expand its utilization are ongoing. These continued improvements in stress and pest tolerance allow for expanded use of this low-input turf species. This review summarizes the history of zoysiagrass in the United States; summarizes species introduction and utilization; addresses and discusses strengths and shortcomings of the species; evaluates breeding history, methodology, and challenges; and suggests future prospects and potential for zoysiagrass.
... However, studies implementing the EL procedure have reported inconsistencies, including the underestimation (Cardona et al. 1997;Fry et al. 1993) and overestimation (Maier et al. 1994a) of freeze tolerance in several warm-season turfgrass species. This suggests the evaluation of regrowth post freezing may be a better option to evaluate freeze tolerance in grasses (Patton and Reicher 2007). ...
... Post-freeze survival of rhizomes, single stolon nodes, whole stolons, and whole-plants have been used to estimate freeze tolerance in turf species (Bush et al. 2000;Dione et al. 2001;Qian et al. 2001;Anderson et al. 2003;Sahba et al. 2003;Patton et al. 2007). In St. Augustinegrass, single-node (Philley et al. 1995;Li et al. 2010), four-node (Maier et al. 1994b), and whole stolons (Milla-Lewis et al. 2013) have been utilized. ...
... Raleigh's superior freeze tolerance is well documented in both field studies and laboratory-based freeze tests (Maier et al. 1994a, b;Philley et al. 1998;Li et al. 2010;Moseley et al. 2010). Genotypes 106T3 and GF2 were selected for their high levels of freezetolerance and semi-dwarf growth habit, and are reported to have similar winter survival to Raleigh in Patton and Reicher (2007) found genotypes classified with intermediate winter injury varied in their response across years, while genotypes exhibiting low or high winter injury were stable. However, it should be noted that in this study, differences in freeze response between the intermediate genotypes were not statistically significant with the exception of Seville. ...
Article
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Winter hardiness is a major-limiting factor for St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] grown in the transitional climatic region of the United States. Lab-based freeze tests that mimic the range of field winter survivability in St. Augustinegrass can contribute to the selection of cold hardy genotypes. This study used a whole container method, four freezing temperatures, and two data collection systems to evaluate the freezing response of nine St. Augustinegrass genotypes ranging in their winter hardiness. Results indicated −3 and −4 °C with average regrowth ratings of 33.6 and 17.8% respectively, were more suitable temperatures for evaluating freeze survival in St. Augustinegrass than −5 and −6 °C with average regrowth ratings of 0.4 and 0%, respectively. Visual ratings of surviving green tissue and regrowth were generally well correlated when evaluated over a six week period post-freeze with Pearson correlation coefficients ranging of 0.17–0.62 for −3 °C freeze tests and 0.79–0.93 for −4 °C freeze tests. Additionally, measurement of percent green cover using digital imaging techniques commonly utilized in turfgrass field studies were significantly correlated (0.66) with visual ratings averaged across weekly post-freeze evaluation measurements for both −3 and −4 °C freezing temperatures. These results provide evidence that digital imaging analyses are useful in estimating surviving green tissue and regrowth in lab-based freeze tests. This study provides additional information regarding freezing temperatures, genotype responses, and data collection methods in St. Augustinegrass, which should aid breeders in the improvement of freeze tolerance in the species.
... Cold tolerance in zoysiagrass species varies with Z. japonica being the most cold-tolerant than Z. matrella, and Z. pacifica being the least cold-tolerant (Patton and Reicher, 2007). Cold tolerance and its molecular mechanism have been widely studied in Arabidopsis and sparsely in Z. japonica. ...
... The cold tolerance ability of the three Zoysia species; Z. japonica, Z. matrella, and Z. pacifica have been evaluated to see the relationship between leaf width and autumn growth with winter injury. It was found that Z. japonica had less winter injury than Z. matrella, followed by Z. pacifica (Patton and Reicher, 2007). However, the most commonly used zoysiagrasses turn brown on the first sign of winter in temperate regions like Korea. ...
Article
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Inducer of CBF (C-repeat binding factors) expression 1, 2 (ICE1/2) is an important transcription factor that plays a significant role in the cold stress response pathway. Zoysiagrasses are warm-season turfgrasses and are prone to browning at the starting of winter. By understanding the cold response mechanism, the cold tolerance of some zoysiagrasses such as Zoysia matrella or Z. pacifica showing less cold hardiness can be improved to withstand low temperatures. Arabidopsis and Z. japonica ICE1, 2 have already been characterized and reported. Using in-silico analysis, we predicted the putative ICE1, 2 genes in Z. matrella and Z. pacifica. The comparative sequence analyses revealed conservation of the bHLH (basic helixloop- helix) domain in the putative ICE1 and ICE2 genes in Z. matrella andZ. pacifica. Also, two copies of ICE2 were seen in Z. matrella. There were huge variations in the immediate regulatory region of the ICE1 and ICE2 genes which may be a reason for different cold tolerance levels in the three Zoysiagrasses. The predicted sequences of the ICE1,2 genes in Z. matrella and Z. pacifica can be utilized to further investigate interactions with CBF3 and their implications in cold stress tolerance, which will provide new insight into molecular mechanisms in regulating cold tolerance.
... The goal behind freezer-based screening methods is to quickly identify potential genotypic differences in freezing survivability in hopes to make selections that reflect/predict the field-based performance. Dunn et al., (1999) and Patton and Reicher (2007) determined a correlation between field-based winter injury and the controlled freezer-based LT 50 values in zoysiagrass. Effective identification of predictors, like LT 50 values, for field information could help provide a more efficient means for selection and cultivar development for winter hardiness in bermudagrass. ...
... Continued evaluation and comparisons of field and controlled laboratory freezing tests could help elucidate the connection between variable years and weather conditions during the winter months. These correlations have only been recorded in zoysiagrass (Patton and Reicher, 2007) and would aid in prescreening plant materials for the field and provide an economic advantage for plant breeders. Lastly, the evaluation of these genotypes shows that a number of available plant introductions and accessions can help to improve winter survivability in both common and African bermudagrass species in an effort to develop more hardy seeded or vegetatively propagated varieties to be used in the transition zone. ...
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DUNNE, JEFFREY COLIN. Breeding for combined shade and cold tolerance in bermudagrass (Cynodon spp.) and the identification of QTL associated with seed head traits. (Under the direction of Dr. Susana Milla-Lewis and Dr. Grady Miller). Bermudagrass (Cynodon spp.) is widely used for recreational and residential turf in the southeastern United States for its superior turf quality and excellent durability. While the grass is considered to have excellent heat and drought tolerances, its ability to survive under shade and freezing temperatures is low. Developing cultivars tolerant to shade would allow bermudagrass to become more prevalent in home lawns or other recreational areas in the southeast, where trees dominate the landscape. Nine accessions collected from Pretoria, South Africa were evaluated for their ability to grow under shade. Significant differences among shade levels, genotypes, and the interaction of the two were observed. As expected, the progression from 0% to 63% to 80% shade reduced normalized difference vegetation index (NDVI), percent turfgrass cover (TC), and turf quality (TQ) readings for all accessions. Some genotypes, however, were able to maintain adequate quality and aggressiveness under 63% shade. Celebration, 'WIN10F' and 'STIL03' performed better than Tifway (P ≤ 0.05), the susceptible control. Further improvement can be attained through the reduction in nitrogen fertility, increased mowing heights, and trinexapac-ethyl (TE) applications. WIN10F, STIL03 and three controls (Celebration, Tifgrand and Tifway) were compared under these management practices. Overall, differences were observed between genotypes, TE applications, mowing heights and fertility across all response variables in both years. Lastly, significant differences were observed for the interactions between entries, TE applications and mowing heights, suggesting that although these cultural practices may provide a reduction in the symptoms of shade stress, the management recommendations are dependent on the genotype and the environment in which the management strategy can be most effective. Development of cultivars with enhanced adaptation to freezing temperatures would constitute a significant improvement in the management of bermudagrass in the transition zone. A trial was established in July 2010 in order to evaluate a set of African and common bermudagrass accessions from the USDA germplasm collection for their winter hardiness. Four commercial cultivars ('Patriot', 'Quickstand', 'Tifsport', and 'Tifway') were included as checks. High levels of winter hardiness were observed among the African bermudagrass germplasm. Plant introductions 290905, 647879, 255447 289923 and 615161 were the top performers with
... The objective behind freezer-based screening methods is to quickly identify genotypic differences in freezing survivability in hopes to make selections that reflect or predict field-based performance. Dunn et al. (1999), Patton and Reicher (2007), and Hinton et al. (2012) determined a correlation between field-based winter injury and the controlled freezer-based LT 50 values in zoysiagrass. Effective identification of predictors, like LT 50 values, for field performance could result in a more efficient means for selection and cultivar development for cold hardiness in bermudagrass. ...
... For instance, plots were evaluated a single time for spring green-up and winterkill in late spring, but other evaluations and weather conditions like disease, moisture content, snow accumulation, and temperature fluctuations play an important role in winter survivability. Prior to this study, correlations between field and controlled freezing tests had only been recorded in zoysiagrass (Dunn et al., 1999;Patton and Reicher, 2007;Hinton et al., 2012). Larger controlled freezing experiments and more comparisons with field-based evaluations may help elucidate the connection between variable years and weather conditions during the winter months. ...
Article
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Bermudagrass [Cynodon spp. (L.) Rich.] is a high-quality, durable turfgrass with excellent heat and drought tolerance. However, its lack of freezing tolerance limits its use in the transition zone. The development of cultivars with enhanced freezing tolerance would constitute a significant improvement in the management of bermudagrass in this region and could extend its area of adaptation further north. There has been substantial work on screening of common-type bermudagrass [Cynodon dactylon (L.) Pers.] germplasm for freezing tolerance, but not for the African (Cynodon transvaalensis Burtt-Davy) germplasm. The purpose of this research was to conduct multiyear field testing and laboratory-based freezing test evaluations of winter hardiness and freezing tolerance, respectively, of an African and common bermudagrass germplasm collection. A high level of cold hardiness was observed among the germplasm in this study. In field evaluations, plant introductions (PIs) PI 290905, PI 647879, PI 255447, PI 289923, and PI 615161 were the top performers, having consistently greater spring green-up and reduced winterkill compared with ‘Patriot’, ‘Tifsport’, ‘Quickstand’, and ‘Tifway’, though not always significantly. A comparison between field-based ratings and calculated lethal temperatures for 50% death (LT50) from laboratory-based freezing tests showed significant correlations of −0.26 and −0.24 for spring green-up and winterkill, respectively, suggesting that these controlled freeze experiments could be used to prescreen materials prior to field testing. Overall, results indicate that some of the PIs evaluated in this study can be used as additional sources of cold hardiness in bermudagrass breeding.
... The objective behind freezer-based screening methods is to quickly identify genotypic differences in freezing survivability in hopes to make selections that reflect or predict field-based performance. Dunn et al. (1999), Patton and Reicher (2007), and Hinton et al. (2012) determined a correlation between field-based winter injury and the controlled freezer-based LT 50 values in zoysiagrass. Effective identification of predictors, like LT 50 values, for field performance could result in a more efficient means for selection and cultivar development for cold hardiness in bermudagrass. ...
... For instance, plots were evaluated a single time for spring green-up and winterkill in late spring, but other evaluations and weather conditions like disease, moisture content, snow accumulation, and temperature fluctuations play an important role in winter survivability. Prior to this study, correlations between field and controlled freezing tests had only been recorded in zoysiagrass (Dunn et al., 1999;Patton and Reicher, 2007;Hinton et al., 2012). Larger controlled freezing experiments and more comparisons with field-based evaluations may help elucidate the connection between variable years and weather conditions during the winter months. ...
... As a result, cold acclimation improves a plant's freezing tolerance. Previous studies have indicated warm-season grass species, including St. Augustinegrass, respond well to cold acclimation (Anderson et al. 1993(Anderson et al. , 1988Fry et al. 1993;Qian et al. 2001;Anderson et al. 2003;Shahba et al. 2003;Patton and Reicher 2007;Li et al. 2010). St. Augustinegrass cultivar 'Raleigh' readily acclimates to cold temperatures (Maier et al. 1994b;Li et al. 2010) and based on the cultivar's freeze response, Li et al. (2010) developed an acclimation protocol for St. Augustinegrass. ...
... Cold acclimation Acclimation at low, non-freezing temperatures typically increased the freezing tolerance of St. Augustinegrass genotypes. This phenomenon has been observed in both cool-season (Dionne et al. 2001;Hoffman et al. 2013) and warm-season grasses (Cardona et al. 1997;Stair et al. 1998;Patton and Reicher 2007) including St. Augustinegrass (Maier et al. 1994b;Li et al. 2010;Milla-Lewis et al. 2012;Kimball et al. 2017). In this study, cold acclimation had the largest effect on genotype response significantly increasing freeze tolerance for Raleigh, GF2, 106T3, Palmetto, and Seville in comparison to NCA plants (Fig. 1). ...
Article
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The adaptation of St. Augustinegrass (Stenotaphrum secundatum [Walt.] Kuntze) in the transitional climatic zone of the United States is limited due to a lack of sufficient freeze tolerance. Lab-based freeze testing provides plant breeders with a reliable method for evaluating freeze tolerance. However, in developing protocols for freeze testing it is important to account for the underlying mechanisms that affect freeze tolerance. The objective of this research was to evaluate the effects of cold acclimation and deacclimation on nine St. Augustinegrass genotypes ranging in their levels of freeze tolerance. Results indicated that accounting for all levels of acclimation provided excellent genotype separation across freezing temperatures (− 3 and − 4 °C) and supports the hypothesis that the inclusion of acclimation response offers the best overall assessment of freeze tolerance. Genotypes with the highest known field winter survival had also the highest improved freeze tolerance upon cold-acclimation. Other genotypes did not respond to cold-acclimation which resulted in poor survival and recovery rates. Conversely, a significant loss of freeze tolerance was identified when plants were subjected to deacclimation events suggesting that St. Augustinegrass can be negatively affected by rapid temperature changes in the transitional climatic zone leading to increased sensitivity to winterkill. Overall, this study provides preliminary information regarding the complex relationships within and between mechanisms affecting freeze tolerance in St. Augustinegrass. Moreover, results presented here should aid in the development of protocols for selection of freeze tolerant breeding materials under controlled environmental conditions.
... The dehydrin expression responses may be associated with hormonal regulation under CA. Great variation exists between zoysiagrass species and cultivars in freezing tolerance (Dunn et al., 1999;Patton and Reicher, 2007;Hinton et al., 2012). Patton and Reicher (2007) reported that the lethal temperature for 50% of grasses (LT 50 ) ranged from −8.4 to −11.5°C among 13 zoysiagrass cultivars. ...
... Great variation exists between zoysiagrass species and cultivars in freezing tolerance (Dunn et al., 1999;Patton and Reicher, 2007;Hinton et al., 2012). Patton and Reicher (2007) reported that the lethal temperature for 50% of grasses (LT 50 ) ranged from −8.4 to −11.5°C among 13 zoysiagrass cultivars. Recently, Okeyo (2010) reported ...
... (Japon çimi) oluşturduğu yüksek kalitedeki çim dokusuyla dünyanın pek çok ülkesinde ev bahçeleri, parklar, golf ve spor sahalarında kullanım bulan önemli bir çim türüdür (Beard, 1973;Richardson, 2003). Sıcak iklim çim bitkileri içinde kışın düşük sıcaklıklara toleransı en iyi tür olan Japon çimi sıfırın altındaki sıcaklıklarda bile yaşamını sürdürebilmektedir (Emmons, 2000;Dunn, 1991;Patton ve Reicher, 2007). Bu bakımdan Japon çimi ülkemizin sadece Akdeniz ve Ege sahil bölgeleri için değil, geçiş iklim bölgelerinde tesis edilecek yeşil alanlar için de oldukça önemli bir potansiyele sahiptir. ...
Conference Paper
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Zoysia japonica Steud. (Zoysiagrass) has a great potential for the Mediterranean and transitional climatic region of Turkey due to its shade tolerance, low maintenance requirements and other superior turfgrass characteristics. However, it is not a well known and commonly used turfgrass species in Turkey. The number of studies on the establishment of zoysiagrass under Mediterranean climatic conditions is limited. The objective of the study was to determine the optimum seeding date for successful establishment of zoysiagrass under the climatic conditions of Mediterranean region of Turkey. Zenith zoysiagrass was seeded on three different dates including June, July and August 2012 at 10 gr/m2 seeding rate in a randomized complete block design with three replications and the study will be repeated in 2013. After seeding, biweekly establishment rate (%) and turfgrass quality (using 1–9 scale, where 9= excellent quality) data were collected and turfgrass density measurement was taken before the onset of dormancy. Based on the first year results; zoysiagrass seeded in June and July established at a rate of 100 and 87% respectively at the end of the first growing season and both dates provided above acceptable turfgrass quality. However zoysiagrass plots seeded in August reached to 48% coverage at the mean time. Zoysiagrass seeded in June provided the highest shoot density with 225 shoots per 50 cm–2, followed by July and August seeding dates with 175 and 103 shoots. Based on the preliminary results, June can be suggested as an optimum seeding date for zoysiagrass under the Mediterranean conditions of Turkey.
... Commonly known as a warm-season turfgrass, Zoysia japonica (2n = 4x = 40) has many remarkable characteristics, including minimal maintenance, excellent tolerance to drought, salinity, and freezing, good ability to conserve water and soil, and excellent traffic tolerance [3][4][5][6][7][8]. Nevertheless, the short green period and unaesthetic appearance during senescence hamper its further popularization and utilization [9,10]. ...
Article
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As a newly described Sillaginidae species, Chinese sillago (Sillago sinica) needs a better understanding of gene annotation information. In this study, we reported the first full-length transcriptome data of S. sinica using the PacBio isoform sequencing Iso-seq and a description of transcriptome structure analysis. A total of 454,979 high-quality full-length transcripts were obtained by single-molecule real-time (SMRT) sequencing, which was corrected by Illumina sequencing data. After that, 66,948 non-redundant full-length transcripts were generated after mapping to the reference genome of S. sinica, including 49 fusion isoforms and 9,250 novel isoforms. 63,459 isoforms were successfully annotated by one of the Nr, Nt, SwissProt, Pfam, KOG, GO, and KEGG databases. Additionally, 30,987 alternative polyadenylation (APA) sites, 451,867 alternative splicing (AS) events, 21,928 long non-coding RNAs (lncRNAs) and 12,911 transcription factors (TFs) were identified. The full-length transcripts of S. sinica would provide a precious resource for characterizing the transcriptome of S. sinica and for the further study of gene function and regulatory mechanism of this species.
... Commonly known as a warm-season turfgrass, Zoysia japonica (2n = 4x = 40) has many remarkable characteristics, including minimal maintenance, excellent tolerance to drought, salinity, and freezing, good ability to conserve water and soil, and excellent traffic tolerance [3][4][5][6][7][8]. Nevertheless, the short green period and unaesthetic appearance during senescence hamper its further popularization and utilization [9,10]. ...
Article
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Background Zoysia japonica is an important warm-season turfgrass used worldwide. Although the draft genome sequence and a vast amount of next-generation sequencing data have been published, the current genome annotation and complete mRNA structure remain incomplete. Therefore, to analyze the full-length transcriptome of Z. japonica , we used the PacBio single-molecule long-read sequencing method in this study. Results First, we generated 37,056 high-confidence non-redundant transcripts from 16,005 gene loci. Next, 32,948 novel transcripts, 913 novel gene loci, 8035 transcription factors, 89 long non-coding RNAs, and 254 fusion transcripts were identified. Furthermore, 15,675 alternative splicing events and 5325 alternative polyadenylation sites were detected. In addition, using bioinformatics analysis, the underlying transcriptional mechanism of senescence was explored based on the revised reference transcriptome. Conclusion This study provides a full-length reference transcriptome of Z. japonica using PacBio single-molecule long-read sequencing for the first time. These results contribute to our knowledge of the transcriptome and improve the knowledge of the reference genome of Z. japonica . This will also facilitate genetic engineering projects using Z. japonica .
... Also, the cold hardiness is one of the shortcomings. Zoysia matrella showed a variable winter injury response, while some germplasm often does not survive at cold wheater (Forbes, 1952;Patton & Reicher, 2007;Patton et al., 2017). Moreover, the seed yield and seed establishment are also a significant disadvantage. ...
Article
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Zoysiagrass (Zoysia spp.) has excellent turf quality and can be applied to various uses for personal space to public sports areas or commercial landscapes. However, it has disadvantages such as slow growth rate, cold hardiness, low seed yield, and hard to establish from seeds, which cannot be improved with agricultural practices. Therefore, breeding a new cultivar as a hybrid could be an efficient strategy to improve the Zoysiagrass cultivar. In fact, hybrid zoysiagrass shows mixed traits of both parents in morphology and heterosis in growth. However, inflorescence appearance and its rate are known to make a hybrid. Thus, the variety of inflorescence appearance timing and production rate were investigated among 549 genetic resources. As a result, only 5.38% of the variety among survived zoysiagrass after transplanting showed more than 30% inflorescence appearance within the given period. During that, some varieties showed a reduction of total inflorescence. Hence, we report the diversity of inflorescence appearance timing and production rate that could be useful for breeders and researchers breeding new Zoysiagrass cultivars.
... Commonly known as a warm-season turfgrass, Zoysia japonica (2n = 4x = 40) has many remarkable characteristics, including minimal maintenance, excellent tolerance to drought, salinity, and freezing, good ability to conserve water and soil, and excellent traffic tolerance (Patton and Reicher, 2007;Teng et al., 2017Teng et al., , 2018. Nevertheless, the short green period and unaesthetic appearance during senescence hamper its further popularization and utilization (Teng et al., 2016(Teng et al., , 2021b. ...
Article
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The degradation of chlorophyll is of great significance to plant growth. The chlorophyll b reductase NOL (NYC1-like) is in charge of catalyzing the degradation of chlorophyll b and maintaining the stability of the photosystem. However, the molecular mechanisms of NOL-mediated chlorophyll degradation, senescence, and photosynthesis and its functions in other metabolic pathways remain unclear, especially in warm-season turfgrass. In this study, ZjNOL was cloned from Zoysia japonica. It is highly expressed in senescent leaves. Subcellular localization investigation showed ZjNOL is localized in the chloroplast and the bimolecular fluorescence complementation (BiFC) results proved ZjNOL interacts with ZjNYC1 in vivo. ZjNOL promoted the accumulation of abscisic acid (ABA) and carbohydrates, and the increase of SAG14 at the transcriptional level. ZjNOL simultaneously led to the excessive accumulation of reactive oxygen species (ROS), the activation of antioxidant enzymes, and the generation of oxidative stress, which in turn accelerated senescence. Chlorophyll fluorescence assay (JIP-test) analysis showed that ZjNOL inhibited photosynthetic efficiency mainly through damage to the oxygen-evolving complex. In total, these results suggest that ZjNOL promotes chlorophyll degradation and senescence and negatively affects the integrity and functionality of the photosystem. It could be a valuable candidate gene for genome editing to cultivate Z. japonica germplasm with prolonged green period and improved photosynthesis efficiency.
... The same laboratory also developed methods to quantify turfgrass color, and has since released a dedicated software platform for turfgrass image analysis (Karcher and Richardson, 2003;Karcher et al., 2017). Use of image analysis to estimate green coverage of a turfgrass canopy has since been widely adopted for use in cultivar evaluation, drought response, freeze tolerance, disease severity, and divot recovery (Karcher and Richardson, 2013;Karcher et al., 2008;Patton and Reicher, 2007;Sykes et al., 2017;Williams et al., 2011). ...
Article
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Objective methods of estimating green coverage using digital image analysis have been used increasingly by turfgrass scientists. The objective of our research was to evaluate the effectiveness of Canopeo, a relatively new smartphone application, for estimating green coverage of bermudagrass ( Cynodon dactylon ) emerging from winter dormancy, with or without colorants. A field study was conducted on a research ‘U3’ bermudagrass fairway in Stillwater, OK, during Spring 2019 and 2020. The experiment was conducted as a randomized complete block design with three colorant treatments: Endurant Fairway (FW), Endurant Perennial Ryegrass (PR), and an untreated control. Green coverage of the turfgrass canopy was determined weekly from mid-March to early May using a digital camera and ImageJ software, and a smartphone and the Canopeo application. Green coverage estimates from Canopeo correlated strongly ( r = 0.91) with those from ImageJ when no colorants were applied. Correlation between Canopeo and ImageJ was diminished under plots treated with colorants. Canopeo is an effective tool for estimating green coverage of living turfgrasses, but additional calibration may be required for acceptable performance when evaluating greenness of colorant-treated turfgrasses.
... Many studies have been conducted to determine the freeze tolerance of bermudagrass in controlled environments by estimating the temperature to kill 50% of the population (LT 50 ) (Anderson et, al., 1993(Anderson et, al., , 2002. The LT 50 values obtained in controlled environment studies showed significant negative correlations to spring green-up and positive correlation to winterkill estimated in the field (Dunne et al., 2019;Patton & Reicher, 2007). Although field evaluations are common for plant breeders to assess winter survivability of a large number of genotypes, environmental conditions in the field are unpredictable and difficult to replicate (Anderson et al., 2002;Wu & Anderson, 2011). ...
Article
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Bermudagrasses (Cynodon spp.) are commonly used in golf courses, athletic fields, and home lawns in the transitional climatic region of the United States. Winterkill, however, is a major concern for bermudagrasses grown in this region. Controlled environment testing is a reliable method to evaluate freeze tolerance contributing to the selection of freeze tolerant genotypes. Therefore, this study was designed to test the freeze tolerance of two elite experimental genotypes, OKC1873 and OKC1406, along with two industry standards (‘Tifway’ and ‘Tahoma 31’), by exposing them to various freeze temperatures (−4 to −14 ℃) in a controlled environment. The freezing test was replicated in time, and the mean lethal temperature to kill 50% of the population (LT50) for each genotype was determined. Tifway (freeze‐sensitive standard) had an LT50 value of −7.0 ℃. The genotype OKC1873 (−7.2 ℃), was in the same statistical group as Tifway. Tahoma 31 was the best‐performing genotype with the lowest LT50 value of −9.1 ℃. The genotype OKC1406 (−8.8 ℃) was in the same statistical group as Tahoma 31. Top‐performing experimental genotypes will move on for further screening in replicated field trials for future consideration for commercial release based on qualities such as improved freeze tolerance, desirable turfgrass quality, and sufficient disease resistance. Controlled environment evaluation of freeze tolerance provides valuable information for breeders to gauge the genetic gain in breeding winter‐hardy bermudagrasses. ‘Tahoma 31’ was the top‐performing cultivar in this study. OKC1406 had an LT50 value significantly lower than ‘Tifway’ and similar to Tahoma 31, indicating superior freeze tolerance.
... Festuca arundinacea Schreb.) cultivars are more adapted to shade and high or low temperatures consistent with landscapes in semiarid climates of the transition zone (Patton 2009, Patton and Reicher 2007, Wu et al. 1985. ...
Article
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Urban soils may restrict turfgrass rooting depth with shallow soil layers in high sand content soils, which may influence water conservation. A greenhouse study sought to quantify water usage and determine the physiological response of turfgrasses at four irrigation levels. ‘ATF-1434′ tall fescue (Schedonorus arundinaceus (Schreb.) Dumort. nom. cons.; syn. Festuca arundinacea Schreb.), ‘Jamur' Japanese lawngrass (Zoysia japonica Steud.), and ‘Zeon' Manilagrass [Zoysia matrella (L.) Merr.] were established in 10 cm (4 in) diameter by 17.8 cm (7 in) tall containers. Each species was irrigated with 16.5, 21.9, 27.3, or 32.7 mm.wk−1 (0.65, 0.86, 1.1, or 1.3 in.wk−1). Gravimetric water loss was determined by pre- and post-irrigation pot weights. Turf quality, leaf discoloration, percent green cover, and gross photosynthesis were evaluated weekly and root parameters were measured at the conclusion of each trial. Although root mass was similar among species, water deficit stress and leaf discoloration occurred sooner in tall fescue than the two Zoysia species, reducing turf quality and green cover. Japanese lawngrass and Manilagrass had greater stomatal conductance, resulting in 109 and 89% higher gross photosynthesis relative to tall fescue. Both zoysiagrasses maintained acceptable turf quality with 27.3 mm water.wk−1. However, tall fescue quality was not acceptable at any irrigation level. Index words: Photosynthesis, gravimetric water loss, tall fescue, Japanese lawngrass, Manilagrass. Species used in this study: Tall fescue (Schedonorus arundinaceus (Schreb.) Dumort. nom. cons.; syn. Festuca arundinacea Schreb.); Japanese lawngrass (Zoysia japonica Steud.); Manilagrass [Zoysia matrella (L.) Merr.].
... The ingredients of the ecological substrate are usually composed of fibers, loam, cement, and a pH-adjusting agent, etc. literature [18] indicated that the ecological substrate can greatly promote the plants' growth, thereby effectively restoring the slope. However, it has been reported that the young plants for slope protection, such as cynodondactylon and zoysiagrass, would stop growing and be fatal to the cold weather, especially when it encounters continuous snow in the winter [19,20]. However, to date, little attention has been paid to the functionality of ecological substrate in protecting the plant growth in extremely cold weather, in contrast to the studies on the vegetative properties of ecological substrate [21,22]. ...
Article
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A new ecological substrate is proposed to achieve a desired electric conduction and heating to protect the slope plants from freeze injury. Expanded polystyrene (EPS), cement, carbon fiber, graphite, and raw soil are the main components of the ecological substrate. The electrical conductivity, heating efficiency, thermo-sensitivity, and heat preservation of the substrate are experimentally investigated. The result shows that the addition of carbon fiber could significantly decrease resistivity of substrate, but the effect of fiber content exceeding 3% on the resistivity of substrate becomes insignificant. Conductive fine materials (i.e., carbon fiber and graphite powder) covering the surface of EPS would result in a significant reduction of the global resistivity of non-dry substrate, but it could only slightly affect the counterpart of the completely dry substrates. The substrate could hardly be formed when the EPS content exceeds 4%. As EPS content increases, the contact surface decreases and the resistivity of the substrate increases. The peak temperature at 30 min of substrate without root is higher than that of substrate with plant roots. Nevertheless, the temperature alteration ratio below 40 °C of substrate with plant root is nearly the same as its counterpart in the substrate without roots. The resistance of the substrate with plant roots increases with the temperature. The resistance of rootless substrate decreases by the heat action of the loosely bound water. EPS particles improve the heat preservation performance of substrate, but the heat preservation performance of substrate degrades with the growth of plants.
... ex Trin) is chosen as the planting object. Zoysiagrass is a kind of important turfgrass and it has some properties, such as freeze tolerance, salt tolerance, and drought resistance, which are of great importance for ecological slope protection [20][21][22]. ...
Article
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Dry-sprayed ecological slope protection technology is an effective mean to restore the ecological environment of rock slope, which has been continuously studied and improved by scholars since its advent. Based on the existing research, a new type of dry-sprayed ecological substrate with carbon fiber and expanded polystyrene (EPS) particles was proposed to achieve lightweight and conductive heating. The ingredients of the ecological substrate are EPS, cement, carbon fiber, graphite powder, soil, water-retaining agent, and pH adjusting agent, respectively. In order to investigate the ecological performance and the physical properties of the substrate, the growth rule of Zoysiagrass was investigated by pot experiment and orthogonal range analysis, and the density and conductivity of the substrate were tested. The result shows that proper EPS particles in the substrate can improve soil structure and promote plant growth, and they play a similar role as soil conditioner. However, when the content of EPS particles exceeds 4%, the substrate is difficult to solidify by cement, which will lead to disintegration. EPS is the main factor affecting the germination and growth of plants, followed by cement, while carbon fiber and graphite powder content effect less. The optimum proportion for plant growth is EPS particle 4%, cement 2.5%, carbon fiber 1%, graphite powder 10%, pH adjusting agent 2.5%, and water retaining agent 0.1%. EPS particles can effectively reduce the density of the substrate and thus reduce weight. The average conductivity of the substrate specimens is 384 Ω·cm, which has great conductivity.
... The performance of zoysiagrasses has been improved dramatically in the recent years (Patton, 2009). Most of the research on zoysiagrass focus on environmental stresses such as cold tolerance (Patton and Reicher, 2007), drought (Beard and Sifers, 1997;Zhang et al., 2013;Fuentealba et al., 2016), salinity (Marcum et al., 1998;Qian et al., 2000), and shade (Wherley et al., 2011;Zhang et al., 2016), and various biotic stresses such as insects (Braman et al., 1994(Braman et al., , 2000Reinert and Engelke, 2001;Eickhoff et al., 2007), diseases (Green et al., 1994), and nematodes (Schwartz et al., 2010). Fertilization and mowing are two of the most common practices in turfgrass management and it is unlikely that all new cultivars will respond similarly to variations in these inputs. ...
Article
As new zoysiagrass (Zoysia spp.) cultivars are released, field studies on N responses and mowing heights conducted over several years under different environments are needed to determine best management practices. This study was initiated to (i) characterize a general response (color, density, turf quality) to N fertilization rate, mowing height, and their interactions among zoysiagrass cultivars; and (ii) establish appropriate mowing height and N rate recommendations for each of the cultivars studied. Four Japanese lawngrass cultivars (Z. japonica Steud.) and four manilagrass cultivars (Z. matrella L. Merr.) were evaluated in Citra, FL, for 4 yr and in Raleigh, NC, for 2 yr under three N rates (73, 171, and 268 kg ha–1 yr–1) and two mowing heights (2.5 and 5.0 cm for Japanese lawngrass; 0.6 and 1.2 cm for manilagrass). Genetic differences were evident among the zoysiagrass cultivars. Nitrogen rate had a greater impact on most of the observed characteristics when the grass was actively growing, but the effect of mowing height was only significant during spring green-up. The medium N rate was suitable for consistent turf performance throughout the year and the effect of increasing N rate from 171 kg ha–1 to 268 kg ha–1 was minimal. Japanese lawngrass and manilagrass can be successfully maintained at 2.5 or 5.0 cm and 0.6 or 1.2 cm, respectively, for equivalent performance during the majority of the year. However, during spring green-up, the lower mowing height may deliver better turf performance.
... Emerald zoysiagrass (Zoysia japonica Steud.) can form high-quality turf because of its great tolerance to high temperatures, drought, pests, and trampling, especially when compared with cold-season grasses (PATTON; REICHER, 2007). According to Zanon and Pires (2010), in the state of São Paulo, Brazil, Emerald zoysiagrass has become a synonym for turfgrass, as once was Bahia grass in the mid-90s, occupying an estimated growing area of 12,000 ha, with 5,000 in São Paulo state, concentrated mainly in the region of Itapetininga. ...
Article
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Nitrogen is the nutrient that provides the best grass growth responses, and proper nitrogen fertilization can enable the formation of sod in less time and firm enough to be handled after harvest. The aim of this study was to evaluate production and nutrient extraction of Emerald zoysiagrass (Zoysia japonica Steud.) according to the splitting of nitrogen doses. Treatments consisted of five doses (0, 150, 300, 450 and 600 kg ha-1) divided in three or six applications., The N dose of 400 kg ha-1 , divided in four applications, provided the formation of Emerald zoysiagrass sods six months after the previous sod harvest. Nutrient extraction by Emerald zoysiagrass occurs in the descending order, at kg ha-1 : N (207) > K (57) > (Ca) > S (27) > P (14) = Mg (14). Resumo-O nitrogênio é o nutriente que proporciona as maiores respostas no crescimento das gramas e a adubação nitrogenada adequada pode proporcionar a formação do tapete em menor tempo e firme para ser manuseado após a colheita. Objetivou-se com o trabalho avaliar a produção e a extração de nutrientes pelos tapetes da grama Esmeralda em função do parcelamento de doses de nitrogênio. O experimento foi realizado em fazenda de produção de grama, em Itapetininga, SP. Os tratamentos foram constituídos por cinco doses de N: 0, 150, 300, 450 e 600 kg ha-1 , divididos em três ou seis aplicações. A dose de 400 kg ha-1 N, parcelada em quatro aplicações, proporcionou a formação de tapetes de grama Esmeralda, seis meses após a colheita do tapete anterior. A extração de nutrientes pela grama esmeralda obedece a seguinte ordem decrescente, em kg ha-1 : N (207) > K (57) > Ca (45) > S (27) > P (14) = Mg (14). Palavras-chave-Gramado, adubação nitrogenada, taxa de cobertura do solo, Zoysia japonica Steud.
... Because zoysiagrass is a tetraploid and the species can hybridize, breeding programs typically observe significant phenotypic variation. Variation in zoysiagrass has been reported to occur for turf quality, seed head density (Schwartz et al. 2009), DNA content (Schwartz et al. 2010a), shade (Morton et al. 1991), salinity (Marcum et al. 1998;Qian et al. 2000), drought (Marcum et al. 1995;White et al. 2001), temperature adaptations (Patton and Reicher 2007), diseases (Green et al. 1994), nematodes (Busey et al. 1982;Schwartz et al. 2010b), insects (Reinert 1992;Braman et al. 2000) and fusilade herbicide (Leon et al. 2014). With the extensive presence of genetic variation within this genus and the development of several breeding programs across the US, it is important to determine the most efficient analytical tools that provide the best accuracy of estimation of genetic parameters. ...
Article
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Randomized complete block (RCB) design is the most widely used experimental design in biological sciences. As number of treatments increases, the block size become larger and it looses the capacity to control the variance within block, which is its original purpose. A method known as post hoc blocking could be used in these cases to improve the genetic parameter estimation and thus obtain an unbiased assessment of the performance of a given treatment. In trufgrass breeding, as other breeding program, this is a common challenge. The goal of this study was to test the capacity of different post hoc blocking designs to improve the genetic parameter estimation of zoysiagrass (Zoysia spp.). We evaluated two post hoc blocking designs; row–column (R–C) and incomplete block (IB) designs on five genotype trials located in Florida. The results showed that post hoc R–C design had superior model fitting than both the original RCB and the post hoc IB designs when studied at the single measurement level and at the site level. The narrow-sense heritability (0.24–0.40) and the genotype-by-measurement correlation (0.57–0.99) did not change significantly when R–C was compared to the original RCB design. The ranking of the top performing genotypes changed considerably when comparing RCB to R–C design, but the degree depended on the location analyzed. We conclude that the change in the ranking of the top (potentially select individuals) is coming from the better control of intra-block environmental variation, and this could potentially have a significant impact on the breeding selection process.
... Zoysia japonica is a widely used warm-season C 4 turfgrass species which owns many excellent characters, such as low maintenance requirements, good traffic tolerance and excellent tolerance to heat, drought, and salinity stresses (Patton and Reicher, 2007;Xu et al., 2015;Teng et al., 2016). However, the shorter green period of Z. japonica compared with cool season turfgrass is becoming a prominent barrier preventing its market promotion in the transition zone and the northern regions. ...
Article
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Senescence is not only an important developmental process, but also a responsive regulation to abiotic and biotic stress for plants. Stay-green protein plays crucial roles in plant senescence and chlorophyll degradation. However, the underlying mechanisms were not well studied, particularly in non-model plants. In this study, a novel stay-green gene, ZjSGR, was isolated from Zoysia japonica. Subcellular localization result demonstrated that ZjSGR was localized in the chloroplasts. Quantitative real-time PCR results together with promoter activity determination using transgenic Arabidopsis confirmed that ZjSGR could be induced by darkness, ABA and MeJA. Its expression levels could also be up-regulated by natural senescence, but suppressed by SA treatments. Overexpression of ZjSGR in Arabidopsis resulted in a rapid yellowing phenotype; complementary experiments proved that ZjSGR was a functional homologue of AtNYE1 from Arabidopsis thaliana. Overexpression of ZjSGR accelerated chlorophyll degradation and impaired photosynthesis in Arabidopsis. Transmission electron microscopy observation revealed that overexpression of ZjSGR decomposed the chloroplasts structure. RNA sequencing analysis showed that ZjSGR could play multiple roles in senescence and chlorophyll degradation by regulating hormone signal transduction and the expression of a large number of senescence and environmental stress related genes. Our study provides a better understanding of the roles of SGRs, and new insight into the senescence and chlorophyll degradation mechanisms in plants.
... Zoysia japonica, which is a common warm-season grass that has minimal maintenance requirements and exhibits excellent traffic tolerance and salt tolerance, is frequently used in warm climatic and transitional regions (Teng et al. 2016a). More widespread use of zoysiagrass could improve the sustainability and decrease the environmental impact of home lawns, football fields, and golf courses (Patton and Reicher 2007). Studies to date have focused on the evaluation of salt tolerance in different turfgrass cultivars and on exploring physiological tolerance mechanisms. ...
Article
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Key message: A novel Zoysia japonica salt-induced glycine-rich RNA-binding protein gene was cloned in this study and its overexpression caused salt sensitivity in transgenic Arabidopsis. Glycine-rich RNA-binding proteins (GRPs) play crucial roles in diverse plant developmental processes. However, the mechanisms and functions of GRPs in salinity stress responses remain largely unknown. In this study, rapid amplification of cDNA end (RACE) PCR methods was adopted to isolate ZjGRP from Zosyia japonica, a salt-tolerant grass species. ZjGRP cDNA was 456 bp in length, corresponding to 151 amino acids. ZjGRP was localized in the nucleus and cytoplasm, and was found particularly abundantly in stomatal guard cells. Quantitative real-time PCR showed that ZjGRP was expressed in the roots, stems, and leaves of Zoysia japonica, with the greatest expression seen in the fast-growing leaves. Furthermore, expression of ZjGRP was strongly induced by treatment with NaCl, ABA, MeJA, and SA. Overexpression of ZjGRP in Arabidopsis reduced the rate of germination and retarded seedling growth. ZjGRP-overexpressing Arabidopsis thaliana exhibited weakened salinity tolerance, likely as a result of effects on ion transportation, osmosis, and antioxidation. This study indicates that ZjGRP plays an essential role in inducing salt sensitivity in transgenic plants.
... 이에 따라 국내 한국잔디의 자생지 현황조사 및 수집을 통해 신품종 개발에 대한 연구들이 진행되고 있고 (Bae et al., 2010), 근연종간 교잡으로 인해 발생한 교잡종 및 변이 종의 특성 연구 및 육종을 통해 영양계 신품종들이 보고되 었다 (Bae et al., 2013;Choi and Yang, 2004;Lee et al., 1997). 이와 같이 변이에 의한 형질에 차이를 보이는 계통 의 선발이 영양계 품종개발의 주요 수단이 되고 있다 (Chung et al., 2013 (Choi et al., 1997;Patton and Reicher, 2007 (Table 3). 다음으로는 들잔디 계통으로 Z1075 (31.2 g m −2 ) > Z1089 (29.1 g m −2 ) > ZN1008 (21.5 g m −2 ) > Z1084 (20.9 g m −2 )> Z1070 (19.8 g m −2 ) > Z1038 (18.8 g m −2 ) 등의 순으로 이는 0.6~13.4 ...
Article
Seeded variety of zoysiagrass has not been bred yet in Korea. Development of seeded zoysiagrass cultivar will be very important for the growth of turfgrass industry internationally as well as domestically. This research was conducted to investigate seed yield and germinability of 102 collected native zoysiagrass ecotypes in South Korea. Two hundred and seventy seven ecotypes were collected from various locations including coastal and mountain areas, while 102 morphologically distinct and seed producing ecotypes were selected and planted in 1m{\times}1m maintenance plots. Seed yield ranged from 0.1 to 32.2g\;m^{-2}. Highest yielding line was a medium leaf type zoysiagrass of Z6011 with 32.2g\;m^{-2}. Most collected lines showed seed germination rates of below 50%. However, Z2095 showed highest germination rate of 78%. Considering germination rate and seed yield, collected lines of Z6011, Z 6015, Z1075, ZN1008, and Z1084, which were mostly medium leaf type and Z. japonica types, showed reasonably high potential to be used as breeding lines for high yield seed varieties of zoysiagrass.
Thesis
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Farklı oranlarda potasyum silikat (PS) ve azot (N) uygulamalarının Japon çiminin (Zoysia japonica Steud.) sonbahar-kış dönemi yeşil çim rengini koruyabilme ve genel çim performansı üzerine etkilerini belirlemek amacıyla 2017-2019 yılları arasında Antalya-Türkiye’de ardışık iki arazi denemesi gerçekleştirilmiştir. Bu maksatla; 3 farklı potasyum silikat oranı (0, 3 ve 6 ml/l), 3 farklı azot oranı (0, 2.5 ve 5 g/m2) ve 2 farklı (2 kere ve 3 kere) uygulama sayısı kullanılmıştır. Deneme, 3 tekerrürlü olarak 3x3x2 faktöriyel düzende tesadüf bloklarında bölünmüş parseller deneme desenine göre kurulmuştur. Bazı çim karakteristiklerinde olumlu etkiler olduğu gözlenmiştir. N+PS uygulamaları kalite, renk, çim yoğunluğu, çim indeks değeri, klorofil içeriği, ilkbaharda yeşillenme oranı ve kök kuru kuru ağırlığı değerlerini kontrole göre sırasıyla %51, %71, %38, %15, %48, %48 ve %123’e kadar artırmış, dormansi oranlarını %78’e kadar azaltmıştır. Uygulamalar bazı besin elementlerinin yaprak konsantrasyonlarını artırmış veya azaltmıştır. Tek başına PS uygulaması, genel çim performansına önemli bir fayda sağlamamıştır. N+PS uygulamaları ise Japon çiminin performansını artırmıştır. En erken yeşillenme ve daha kısa dormansi sürelerinin yüksek oranda N+PS uygulamalarında elde edilmesiyle bu uygulamaların kalite, renk ve kullanılabilirliği artırmada etkili olduğu kanaatine varılmıştır. Sonuçlar N+PS uygulamalarının sonbaharda daha geç dormansiye girme ve ilkbaharda daha erken yeşillenmeye neden olarak Japon çiminin dormansi süresini kısaltması nedeniyle, yeşil bir görünüm sağlamak için başvurulan ve pahalı bir uygulama olan üstten tohumlama (overseeding) işlemine alternatif olabileceğine işaret etmektedir. Dormansi süresinin kısaltılması ile Japon çiminin yeşil alanlarda kullanımının yaygınlaşacağı düşünülmektedir. ----- Two consecutive field trials were carried out in Antalya-Turkey from 2017 to 2019 to investigate the effect of different potassium silicate (PS) and nitrogen (N) rates on fall-winter color retention and overall turfgrass performance of Zoysiagrass (Zoysia japonica Steud.). For this purpose, 3 potassium silicate rates (0, 3, and 6 ml/l), 3 N rates (0, 2.5, and 5 g/m2) and 2 application numbers (2 times and 3 times) were used. The trial was set up according to a randomized split-plot design in 3x3x2 factorial order with three replications. Positive effects were observed in some turfgrass characteristics. N+PS applications increased quality, color, grass density, grass index value, chlorophyll content, spring green-up rate, and root dry weight up to 51%, 71%, 38%, 15%, 48%, 48%, and 123%, respectively and decreased dormancy rates up to 78% compared to control. Applications increased or decreased leaf concentrations of some nutrients. Alone PS applications did not significantly affect overall turfgrass performance. N+PS applications increased the performance of Zoysiagrass. It was concluded that high dose of N+PS applications were effective in increasing quality, color, and usability by obtaining the earliest spring green-up and shorter dormancy periods in these applications. The results indicate that N+PS applications may be an alternative to overseeding, which is an expensive application that is used to provide a green coverage, due to the shortening of the dormancy period of Zoysiagrass by inducing later dormancy in the fall and earlier spring green-up. It is thought that the use of Zoysiagrass in green areas will become widespread by the shortening of the dormancy period.
Article
A 10‐year, four‐phase collaborative effort among three universities was conducted to develop new hybrid zoysiagrasses (Zoysia spp. Willd.) with improved turf quality, winter hardiness and pest resistance in comparison to commercial zoysiagrass cultivars, especially ‘Meyer’ (Z. japonica Steud.). In Phase‐1, breeding efforts produced 2,858 new progeny that were evaluated for two years across three sites. In Phase‐2, only 60 (2%) of 2,858 progeny were selected for advancement to 10 replicated multi‐year field trials (Phase‐3). Phase‐3 revealed 10 promising progeny (assigned DALZ numbers) that required further intensive field and laboratory testing in Phase‐4. Phase‐4 revealed differences in establishment rate, and DALZ 1701, 1702, 1707, and 1810 had moderate‐to‐good turf performance across seven sites, while DALZ 1808 had similar or slightly lower performance. Meyer consistently performed poorly and ‘Innovation’, a recently released hybrid cultivar, had poor‐to‐moderate performance in comparison to the experimental genotypes, which illustrates the improvements achieved in zoysiagrass breeding in the last 10 years. Freeze tolerance (LT50, lethal temperature killing 50% of the plants) ranged from −9.8°C (Diamond) to −14.1°C (DALZ 1812) with a mean of −12.5°C. Evidence of large patch [Rhizoctonia solani Kühn, anastomosis Group (AG) 2‐2 LP] in the top 10 DALZ genotypes was 15 to 40% lower than Meyer on several dates. Results indicate that there are multiple genotypes for potential release in the future with improved turf color, winter hardiness, freeze tolerance, large patch resistance, and finer leaf texture suitable for USDA plant hardiness zones ranging between 5b and 8a. This article is protected by copyright. All rights reserved Multi‐disciplinary, systematic breeding efforts effectively improve zoysiagrass. Intra‐ and inter‐specific hybridization introgressed superior turf traits. Multiple options exist for potential zoysiagrass release for a variety of climates.
Chapter
Cold temperatures often severely restrict the growth, distribution, and productivity of plants. The freezing tolerance of plants from temperate climates can be improved by undergoing periods of cold acclimation. Lipids play an important role in the mechanism of frost or cold tolerance in plants. Lipids are widely distributed in the plant kingdom. They are found in abundance in reproductive tissues (e.g., seeds and fruits) of some higher plants where they form important reserve food material such cotyledon of sunflower, rape, peanuts, and almond; endosperm of castor beans, coconut plants, etc.; and mesocarp of avocado pears. Plant membrane lipids have the tendency to change from gel to liquid crystalline phase in response to low-temperature stress. This process is due to the increased level of lipid desaturation. The responsible components of this process are, among others, the fatty acid desaturases. Controlling the activity of these enzymes affects the amount of polyunsaturated fatty acids on the glycerol backbone and eventually controls the plant sensitivity to low-temperature stress. These metabolic processes trigger a series of changes at the transcriptional level, causing differential expression in genes. Numerous approaches toward this process from chemical to the advanced mass spectrometry were taken during the past decades. Metabolomics and transcriptomics seem to be the keys toward describing these complex mechanisms and providing the necessary understanding of lipid metabolic response to low-temperature stress.KeywordsRole of lipids in plantEffect of lipid metabolism to cold stressEffects of cold stress on different plantsRole of lipid signaling in stress responseRole of free ftty acid in signalingRole of lipid in mitigating cold stressMechanism of temperature adaptationCold stress symptomsSensing and strategiesRole of triglycerides to cold responseGlycerolipid response to freezing temperatureLipid hydrolysis under low-temperature stress
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A 3-year experiment was conducted to evaluate the performance and playability of 24 coarse-textured zoysiagrass (Zoysia spp. Willd.) experimental genotypes in comparison to five commercially available cultivars maintained as a low-maintenance turf across multiple climates (Indiana, North Carolina, Georgia, Arizona, and California). Following establishment in 2018, plots were maintained under low-maintenance regimes and evaluated for quality, density, uniformity, color, winterkill damage, drought resistance, and golf ball lie in 2019 and 2020. A turf performance index (TPI) was calculated for each treatment at each site, which represented the number of times the treatment occurred in the top statistical group. The unique climate for each site led to differences in TPI scores. For instance, the arid climates of Arizona and California resulted in distinct differences in performance among treatments compared to the other sites. However, consistencies in performance across sites were also observed. For example, the 2018−2019 winter resulted in winterkill differences among entries in both Indiana and North Carolina, which led to some similarities in TPI. Furthermore, the southern humid climates of North Carolina and Georgia produced consistencies in overall TPI. Under the minimal inputs and the hot-humid or arid climates evaluated in this study, all of the check cultivars were some of the poorest performing treatments, which clearly illustrates there is a need for breeding programs to develop zoysiagrass genotypes for these climates. However, experimental lines that exhibited excellent persistence under these conditions were identified indicating the genetic potential for wider adaptation to lower input environments exists within the species.
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Abiotic stress greatly affects plant growth and developmental processes, resulting in poor productivity. A variety of basic helix-loop-helix (bHLH) transcription factors (TFs) that play important roles in plant abiotic stress response pathways have been identified. However, bHLH proteins of Zoysia japonica, one of the warm-season turfgrasses, have not been widely studied. In this study, 141 bHLH genes (ZjbHLHs) were identified and classified into 22 subfamilies. The ZjbHLHs were mapped on 19 chromosomes except for Chr17 and one pair of the tandemly arrayed genes was identified on Chr06. Also, the co-linearity of ZjbHLHs was found to have been driven mostly by segmental duplication events. The subfamily IIIb genes of our present interest, possessed various stress responsive cis-elements in their promoters. ZjbHLH076/ZjICE1, a MYC-type bHLH TF in subfamily IIIb was analyzed by overexpression and its loss-of-function via overexpressing a short ZjbHLH076/ZjICE1 fragment in the antisense direction. The overexpression of ZjbHLH076/ZjICE1 enhanced the tolerance to cold and salinity stress in the transgenic Z. japonica plants. However, the anti-sense expression of ZjbHLH076/ZjICE1 showed sensitive to these abiotic stresses. These results suggest that ZjbHLH076/ZjICE1 would be a promising candidate for the molecular breeding program to improve the abiotic stress tolerance of Z. japonica.
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Thirty fine‐textured inter‐ and intra‐specific zoysiagrass (Zoysia spp.) hybrids and eight Z. pacifica (Goudsw.) M. Hotta & S. Kuroki genotypes were tested in comparison to Z. matrella (L.) Merr. cultivars, ‘Diamond’ and 'L1F’, for their performance under low‐input golf course putting green management practices from 2014 to 2018 in Dallas, TX. Turfgrass quality, shoot density, genetic color, fall color, spring greenup, and winter survival were visually rated on a 1 to 9 scale (9 = high quality, dark green, very dense, and complete greenup). Seedheads were rated in spring, summer, and fall as a percentage of plot cover. Thirteen elite hybrids from seven different pedigrees were selected, and ball roll distance was measured 8 times between 15 Aug. and 14 Sept. in 2017. Clear statistical differences were not observed among pedigrees for most traits except seedhead production under the low‐input management conditions. However, strong genotype differences were evident. The results suggest under‐utilized species could be exploited by plant breeders to use as parental lines and develop hybrids with desirable traits such as finer leaf texture, low seedhead production, fall color retention and early spring green up. One Z. minima (Colenso) Zotov × Z. matrella hybrid and one (Z. minima × Z. matrella) × Z. japonica Steud. hybrid have been advanced to the 2019 National Warm‐Season Putting Green Trial conducted by NTEP for multi‐location and multi‐year performance testing. This article is protected by copyright. All rights reserved
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Growth and developmental parameters of the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), were evaluated on 41 new zoysiagrass taxa (Zoysia spp. Willd.), which belong to an increasingly popular group of warm-season turfgrasses, in comparison with 5 commercially available zoysiagrass taxa and 1 known susceptible Paspalum L. taxon. Results from two no-choice growth chamber trials indicated that the new Zoysia japonica Steud. taxa were unfavorable for the development of fall armyworm larvae in general compared with the susceptible Paspalum taxon. This was evidenced by significantly lower larval and pupal weights and survival and longer time to pupation and adult emergence, pointing to antibiosis in these zoysiagrass taxa. The new Zoysia matrella (L.) Merr., Zoysia macrostachya Franch. & Sav., and Zoysia sinica Hance taxa seemed more favorable than Z. japonica taxa, as evidenced by numerically higher larval and pupal weights and survival and shorter duration to pupation and adult emergence. Taxa that consistently showed low larval survival were identified for further testing.
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St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] is a commonly used warm‐season turfgrass for lawns in warm‐humid to tropical climates. Efforts to breed improved cultivars with enhanced abiotic and biotic stress tolerance are ongoing, but additional data on their growth and adaptation is needed. Twenty‐one commercially available St. Augustinegrass cultivars and eight experimental genotypes were planted in the field in Fayetteville, AR in both 2009 and 2010 to study their stolon, leaf, and establishment characteristics as well as winter survival. ‘Floratam’, ‘Floralawn’, ‘FX‐10’, ‘FA‐40’ (Mercedes™), ‘B12’ (Sapphire®), and WS had the highest stolon growth rate (>8.9 mm d−1), while ‘TR 6–10’ (Amerishade®), ‘6‐72‐99’ (Delmar™), ‘6‐72‐182’ (Jade™), ‘6‐72‐130’ (Sunclipse™), 106G3, 106T3, and SV27 had the lowest stolon growth rate (<5.1 mm d−1). Cultivars ‘Floraverde’, Floralawn, Floratam, B12 (Sapphire), and ‘Texas Common’ were the quickest to establish. Principal component analysis (PCA) identified that cultivars with similar ploidy levels had similar growth characteristics as increasing ploidy resulted in wider and longer leaves as well as larger stolon diameter and internode length. Cultivars considered dwarf types with short stolons or narrow‐short leaves grouped separately from cultivars with long stolons or wide‐long leaves. Genotypes VNS (Classic™), GF, VNS (Majestic™), ‘SS‐100’ (Palmetto®), ‘Raleigh’, TAES 5714, and Texas Common showed the highest winter survival and associated coverage after winter in both years. Results from this study are intended to help turfgrass breeders, turf producers, practitioners, and homeowners make informed cultivar selection decisions. Planting well‐adapted cultivars will reduce reestablishment costs from winterkill and ultimately increase sustainability. This article is protected by copyright. All rights reserved
Article
Zoysiagrass (Zoysia japonica Steud.) is a warm-season turfgrass species well adapted for lawns and golf courses in transition zone and other regions with warm climates; however, it losses color and goes into dormancy in late fall and winter. The physiological mechanisms of cold acclimation (CA) have not been well understood. This growth chamber study was designed to investigate changes in leaf polyamines (PAs) and activities of selected enzymes, and ethylene production in response to CA. Leaf chlorophyll content and photosynthesis rate declined and cell membrane electrolyte leakage and malondialdehyde increased during CA. Putrescine (Put) and spermidine declined and then increased after 10 days during CA. Ethylene increases after 15 days of CA. Put biosynthesis enzymes (arginine decarboxylase, ADC, ornithine decarboxylase, ODC, s-adenosylmethionine decarboxylase), and diamine oxidases and polyamine oxidase activities increased in response to CA, except for ADC which increased after 10 days of CA. Accumulation of O2- and H2O2 in leaf tissue was observed during CA. These results suggest that PAs and ethylene are involved in CA in zoysiagrass.
Article
‘DALZ 1308’ (Reg. no. CV‐285, PI 691612) is a first‐generation interspecific hybrid developed in 2004 by crossing a genotype of Zoysia minima (Colenso) Zotov and Z. matrella (L.) Merr. ‘Diamond.’ After field evaluations in Dallas, TX (2004–2009) and Gainesville, FL (2006–2008), DALZ 1308 was selected for advancement to the 2013 Warm‐season Putting Greens National Turfgrass Evaluation Program (NTEP). DALZ 1308 was evaluated at 10 NTEP locations (2013–2018) as well as in Dallas, TX (2014–2017) and Gainesville, FL (2013–2017). DALZ 1308 exhibited a diminutive growth habit with narrower and shorter leaf blades and dwarf canopy height as compared to Diamond and L1F; shorter internode length, smaller node, and smaller internode diameter as compared to L1F; superior ball roll as compared to Diamond and L1F in Arizona, Kentucky, and Texas; resistance to tawny mole crickets; and reduced seedhead incidence and density during the growing season. As compared to Diamond and L1F, DALZ 1308 has shown to have reduced winter injury with fabric cover in Bloomington, IN. Although characteristics varied by location, DALZ 1308 exhibits good turfgrass quality, high shoot density, medium‐green genetic color, and extended fall and winter color retention. Initial greenhouse experimentation under moderate shade shows that DALZ 1308 has a greater percent green cover as compared to ‘Palisades’, Diamond, and ‘Zorro’. Overall, DALZ 1308 is an ultradwarf zoysiagrass suitable for golf course putting greens in a wide range of environments across the United States.
Article
ICE1 (Inducer of CBF Expression 1) is a regulator of cold-induced transcriptome, which plays an important role in plant cold response pathway. To enhance the cold tolerance of Zoysia japonica, one of the warm-season turfgrasses, it is helpful to understand the cold response mechanism in Zoysia japonica. We identified stress-responsive ZjICE1 from Zoysia japonica and characterized its function in cold stress. Our results showed that ZjICE1 shared the typical feature of ICE homolog proteins belonging to a nucleic protein. Transactivation activity assay revealed that ZjICE1 bound to the MYC cis-element in the ZjDREB1's promotor. The ZjICE1 overexpressed transgenic Arabidopsis showed enhanced tolerance to cold stress with an increases in SOD, POD, and free proline content and reduction in MDA content. They also induced the transcripts abundance of cold-responsive genes (CBF1, CBF2, CBF3, COR47A, KIN1, and RD29A) after cold treatment. These results suggest that ZjICE1 is a positive regulator in Zoysia japonica plant during cold stress and can be a useful gene for the molecular breeding program to develop the cold tolerant zoysiagrass. Furthermore, the ZjICE1 also conferred resistance to salt and drought stresses, providing the better understanding of the basic helix-loop-helix (bHLH) gene family in abiotic stress responses.
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Zoysiagrasses (Zoysia spp. Willd.) are warm season perennial turfgrasses originating in the Pacific Rim and well-adapted for use in the warm-humid and transitional climatic zones of the United States as both ornamental and recreational turfgrasses. Their low growth habit and general tolerance of many abiotic stresses such as drought, shade, and salinity make them desirable for home and commercial use. However, the use of zoysiagrasses is limited to warm-humid climates because of their relative lack of freezing tolerance compared to cool-season grasses. Limited progress has been made in the development of new winter hardy cultivars which is due in part to the complexity of the trait and a lack of efficient selection criteria. Further investigation into physiological processes that influence freeze tolerance, such as cold acclimation, is needed to improve understanding of this complex trait. In addition, the identification of molecular markers linked to genomic regions controlling freeze tolerance would allow the application of marker assisted selection strategies for the development of zoysiagrass cultivars with improved winter survival. To investigate the relationship between cold acclimation and freeze tolerance in zoysiagrasses, selected cultivars with a reported range of freeze susceptibility were exposed to two cold acclimation treatments and evaluated in four controlled freezing chambers at-8,-9,-10, and-11ºC. Results indicated that cold acclimation has a significant influence on the freeze response of these cultivars. The interaction between cultivar and acclimation treatment was highly significant (p=0.0037). While significant differences in cultivar response were recorded for acclimated plants (p=0.0300), there were no significant differences among cultivars for
Article
Zoysiagrass (Zoysia japonica Steud.) leaves lose their green colour as they undergo cold acclimation (CA) in late fall in many regions, and delaying leaf senescence can extend their green period. The objective of this study was to investigate whether exogenous spermidine (Spd) and spermine (Spm) can delay leaf senescence by enhancing reactive oxygen species (ROS)-scavenging antioxidant enzyme activity. Mature zoysiagrass (cv. Zenith) plants were treated with Spm (1 mM) or Spd (1 mM) or water (control). The treated plants were grown under normal conditions or subjected to cold acclimation CA for 35 days. CA treatment increased leaf electrolyte leakage (EL) and malondialdehyde (MDA) level, decreased chlorophyll (Chl) content, and induced leaf senescence. Foliar application of Spd and Spm reduced the decline in Chl content and reduced EL and MDA levels. CA treatment increased the ROS level and reduced antioxidant enzyme activity. Application of Spm and Spd reduced ROS accumulation and enhanced the activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase under CA conditions. The results of this study indicated that exogenous Spd and Spm at 1 mM can delay CA-induced leaf senescence through enhancement of ROS-scavenging antioxidant activity in zoysiagrass.
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Zoysiagrasses (Zoysia spp.) are warm season turfgrasses primarily grown in the southern and transition zones of the United States. An understanding of the physiological changes that zoysiagrasses undergo during cold acclimation may shed light on physiological phenotypic traits useful in selection of freeze tolerant genotypes. We investigated the relationship between cold acclimation, protein expression, and freeze tolerance in cold-acclimated (CA) and non-acclimated (NCA) plants of Zoysia japonica Steud. cultivars ‘Meyer’ (freeze-tolerant) and ‘Victoria’ (freeze-susceptible). Freeze tolerance was assessed using chambers reaching -6, -8, -10, and -12ºC. Additionally, meristematic tissues from the grass crowns of ‘Meyer’ and ‘Victoria’ were harvested for proteomic analysis after a four week cold acclimation period. Freeze testing indicated that cold acclimation accounted for a 1.9-fold increase in plant survival compared to the non-acclimation treatment. Overall, proteomic analysis identified 62 protein spots having at least a twofold change in abundance under cold acclimation. Nine and 22 unique protein spots were identified for Meyer and Victoria, respectively, with increased abundance (up-regulated) or decreased abundance (down-regulated). In addition, 23 shared protein spots were found among the two cultivars having differential expression in response to cold acclimation. In Meyer, protein response to cold acclimation was primarily upregulated, while in Victoria, protein response was primarily downregulated. These cold acclimation responsive proteins were found to be involved primarily in transcription, metabolism, protein destination and storage, and energy production. As identified through MALDI-TOF/TOF mass spectrometry followed matching of protein homologues against the NCBI Arabidopsis database, major proteins of interest for their association with cold acclimation were LEA 3, MAPK, SOD, GAST1, Phytochrome A, ATP synthase, AGP, PLD, and PSII. Further investigation of these proteins and their functional categories may contribute to increase our understanding of the differences in freezing tolerance among zoysiagrass germplasm.
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Tall fescue is a widely used cool season turfgrass. In this study, we screened freezing tolerance of six tall fescue cultivars based on TEL50 (temperature causing 50% electrolyte leakage). We observed that freezing tolerant tall fescue cultivar exhibited lower EL, accumulated higher soluble sugar and proline, and showed higher CAT and SOD activities when compared with freezing intolerant cultivar. Based on bioinformatics analysis, 6 FaDREB1 unigenes were identified from publicly available transcriptomic data. Expression profiles showed that freezing tolerant cultivar only activated specific FaDREB1 unigenes, while freezing intolerant cultivar activated all six FaDREB1s during cold acclimation period. These findings indicated that cold stress modulated diverse physiological process in different tall fescue cultivars and activated various gene networks through regulating different subsets of FaDREB1s.
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Zoysia matrella (L.) Merr. is a homoploid turfgrass that possesses intermediate traits between Z. japonica Steudel and Z. pacifica (Goudswaard) M. Hotta and Kuroki [syn. Z. matrella (L.) Merr. var. pacifica Goudswaard]. Consequently, it contributes to the growing range of variation that exists within this species. Self-pollination reduces genetic load and can express genetic variance, enabling easy identification and selection for desired traits. The aim of this study was to evaluate the effects of self-pollination of Z. matrella ‘Wakaba’ on morphological traits, genetic structure, and the possible selection of lines with superior traits in S1 progeny. Nine morphological characteristics (plant height, leaf width and length, stolon diameter and internode length, inflorescence number, ground covering, normalized difference vegetation index, and leaf color) were evaluated in the 364 S1 progeny. We have obtained S1 progeny exhibiting wide variation in morphological characteristics and moderate inbreeding depression in almost all traits after self-pollination. To infer genetic structure, a total of 26 simple sequence repeat markers were used, and Bayesian-based structure analysis grouped the progeny into three clusters. Genetic markers revealed that the level of homozygosity increased in S1 progeny caused by inbreeding. Superior progeny that exhibited high ground covering, late winter dormancy, and stay green throughout the entire winter season were selected. Self-pollination can be used for the selection of desirable traits from highly heterozygous species such as Z. matrella. Moreover, we expect that these superior progeny could be used in further study on quantitative trait loci analysis.
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KSUZ 0802 (Reg. No. CV-282, PI 678793) is a fine-textured, cold-tolerant zoysiagrass (Zoysia spp.) hybrid co-developed and jointly released by Texas A&M AgriLife Research, Dallas, TX, and the Kansas Agricultural Experiment Station, Manhattan, KS. KSUZ 0802 is an F1 interspecific hybrid developed in 2001 from a cross between Zoysia matrella (L). Merr. ‘Cavalier’ and an ecotype of Z. japonica Steud. named Anderson 1, a derivative of ‘Chinese Common’. After years of testing (2004 –2008) for turf quality and winter survival at Manhattan, KS, KSUZ 0802 was advanced to a nine location test (2009 –2012) in the transition zone (Wichita and Manhattan, KS, Columbia, MO, Fletcher and Jackson Springs, NC, Stillwater, OK, Knoxville, TN, Virginia Beach and Blacksburg, VA, and Dallas, TX. The freezing tolerance, spring green-up, and fall color retention of KSUZ 0802 is equivalent to ‘Meyer’, but KSUZ 0802 has a finer leaf texture. KSUZ 0802 is also superior to Meyer for turf quality and resistance to bluegrass billbug damage. KSUZ 0802 is well suited for use on golf course fairways and tees, home lawns, and other recreational areas in the transition zone.
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Appropriately designed and installed guardrails are structures that enhance motorist safety; however, their inherent design requires additional vegetation management inputs to maintain safe, acceptable driving conditions. Establishing low-growing, perennial vegetation under guardrails may reduce long-term management inputs. Field research was initiated 17 Dec. 2012 and 3 Dec. 2013 along guardrails in Chatham, Lee, and Yadkin Counties, NC, to evaluate the effect of establishment timing (December, March, April, or May) and soil preparation technique (tillage alone, tillage + bed preparation, or vegetation strip) on ‘El Toro’ (Zoysia japonica Steud.) and ‘Zeon’ [Zoysia matrella (L.) Merr.] zoysiagrass sod establishment and spread along guardrails. Sod establishment in year 1 was successful (>60% cover) across cultivars, locations, and techniques at December and March timings, with cover ranging from 64 to 90% at 90 wk after initial establishment. April and May timings resulted in inconsistent establishment success and are not recommended for North Carolina. Year 2 sodding generally resulted in unsuccessful establishment, which may be due in part to colder winter and dryer spring-summer conditions compared with year 1. Overall, El Toro sod more readily established and spread than Zeon, suggesting that it is a better species for establishment along guardrails. Tillage alone resulted in equivalent or greater sod establishment and spread than tillage + bed preparation and vegetation stripping, and it also requires fewer equipment and personnel inputs. Results suggest that El Toro sod planted in March following soil tillage is the most promising practice for establishment along North Carolina guardrails; however, water inputs may be required during moisture-deficient periods following planting. © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA All rights reserved.
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The cold hardiness of 6 cool season grass genera was compared in mid-winter under controlled freezing conditions. Creeping bentgrasses (Agrostis palustris Huds.) tolerated the lowest temperatures whereas perennial ryegrasses (Lolium perenne L.) was the least hardy. Kentucky bluegrass (Poa pratensis L.) readily loses cold hardiness when exposed to warm conditions and did not reharden when exposed to cool temperatures. Appreciable hardiness in Kentucky bluegrass was induced by simulating drought conditions.
Article
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Electrolyte leakage and regrowth tests were used to estimate cold hardiness levels of field-grown ‘Midiron’ and ‘Tifgreen’ bermudagrass ( Cynodon dactylon × C. transvaalensis crowns. The two procedures were in close agreement. ‘Midiron’ was hardier than ‘Tifgreen’ on all sampling dates. Greatest levels of freeze tolerance were –11°C for ‘Midiron’ and –7° for Tifgreen’ during December and January, ‘Midiron’ was killed at –5° in early June while ‘Tifgreen’ had lost all freeze tolerance by this date. Although the electrolyte leakage procedure was rapid and required no greenhouse space, it was relatively difficult to set up and evaluate.
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Rhizomes of zoysiagrass (Zoysia spp.) were subjected to controlled freezing tests in Jan. and Mar. 1993 and 1994 to determine their low-temperature tolerance. In 1994, 'Belair', 'Korean Common', 'Meyer', and 'TGS-W10' rhizomes survived temperatures as low as -18 °C, while rhizomes of 'Sunburst' survived -14 °C. 'Cavalier', 'Crowne', 'Palisades', 'Emerald', and 'El Toro' were killed at -10 °C or warmer temperatures. Entries surviving exposure to-14 to-18 °C in 1994 controlled freezing tests received postwinter survival ratings in the field of 6.7 to 8.7 (9 = 100% green). Entries killed at higher freezing test temperatures were slower to recover after winter in the field, with ratings of 2.0 to 3.0. Shoot number produced after freezing was a better measurement for assessing low temperature tolerance than was shoot mass. Controlled freezing tests, using regrowth as a measure of hardiness, appear to be useful for identifying low temperature tolerance of zoysiagrasses in the early years of a field study.
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NO information is available regarding endogenous soluble carbohydrate accumulation in buffalograss [Buchloe dactyloides (Nutt.) Engelm.] during cold acclimation. The objective of this study was to determine composition of soluble carbohydrates and their relationship to freezing tolerance in two buffalograss cultivars, 609 and NE 91-118, with different freezing tolerances. The experiment was conducted under natural cold acclimation conditions in two consecutive years in Fort Collins, Colo. Based upon average LT 50 (subfreezing temperature resulting in 50% mortality) from seven sampling intervals in 1998-99 and six sampling intervals in 1999-2000, 'NE 91-118' survived 4.5°C and 4.9°C colder temperatures than '609', during the 1998-1999 and 1999-2000 winter seasons, respectively. Glucose, fructose, sucrose, and raffinose were found in both cultivars in both years, and were generally higher in acclimated than pre- and post-acclimated stolons. Stachyose was not present in sufficient quantities for quantification. Cultivar NE 91-118 contained 63% to 77% more glucose and 41% to 51% more raffinose than '609' in the 1998-99 and 1999-2000 winter seasons, respectively. In 1999-2000, fructose content in 'NE 91-118' was significantly higher than that of '609'. A significant negative correlation was found between LT 50 vs. all carbohydrates in 1999-2000, and LT 50 vs. sucrose and raffinose in 1998-99. Results suggest that soluble carbohydrates are important in freezing tolerance of buffalograss.
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A barrier, to widespread zoysiagrass (Zoysia spp.) use is its slow establishment rate. Our objectives were to quantify differences in establishment rate of zoysiagrass cultivars and genotypes as well as determine the underlying factors associated with differential growth rates. Thirty-five genotypes of zoysiagrass were transplanted into field plots in June 2004 and 2005. Establishment rate and stolon growth of zoysiagrass grass genotypes were measured in the field and then four cultivars with contrasting establishment rate were used for further growth analysis in a growth chamber: Mean establishment rate [log(e) (coverage) d(-1)] and coverage (cm(2)) 91 d after planting (DAP) in the field were faster for Z. japonica. than Z. matrella genotypes. The Z. japonica Genotype 6186 had the greatest coverage 91 DAP. 'EI Toro', 'Chinese Common', and 'Palisades' were among the Z. japonica genotypes that produced more coverage 91 DAP than the mean (1943 cm(2)), while 'Meyer' produced, less coverage than the mean. 'Zorro' was among the fastest establishing Z. matrella genotypes, and 'Diamond' was the slowest. Growth analysis indicated EI Toro and Zorro, which establish faster than Meyer and Diamond, partition more dry matter to stolons and rhizomes than leaves. This is consistent with field data where Ell Toro and Zorro have greater total stolon length than Meyer and Diamond. Zoysiagrass genotypes that partition more dry matter to stems instead of leaves, establish the quickest.
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The objective of this study was to clarify the changes in the contents of endogenous carbohydrates and proline in the stolons and leaves of centipedegrass (Eremochloa ophiuroides (Munro) Hack.), during the natural cold acclimation (hardening) and de-acclimation (dehardening) in relation to freezing tolerance in the field at the transition zone between temperate and subtropical areas in China. The contents of carbohydrates and proline, and freezing tolerance estimated by LT50, which is the temperature at which 50% of the electrolytes in the organ was measured in the leachate, were determined at 10-day intervals from October 1, 2001 to April 18, 2002. It was indicated that the freezing tolerance of stolons increased (LT50 of stolons decreased) quickly, as temperature dropped before winter, but that of leaves which senesced along with the drop in temperature did not. The freezing tolerance of stolons decreased gradually along with the rise in temperature above 5 °C in spring, when the overwintered plants started to grow. The contents of proline and soluble carbohydrates, including sucrose, fructose and glucose, increased as LT50 decreased when temperature dropped below 5 °C before winter, and decreased as LT50 increased in early spring. Correlation analysis revealed that the freezing tolerance of stolons of centipedegrass significantly and positively correlated with the contents of proline and soluble carbohydrates, and the ratio of the soluble carbohydrates to starch. Thus, the freezing tolerance of stolons, which are critical organs that determine the winter surviving ability, largely depended on the content of soluble carbohydrates and the ratio of soluble carbohydrates to starch in centipedegrass. The possible relationship between freezing tolerance and carbohydrate metabolism was also discussed.
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Bermudagrasses, Cynodon sp., are susceptible to winter injury in the transition zone for warm- and cool-season turfgrasses. Our objectives were to determine relative freeze tolerance of recently released and standard cultivars using laboratory-based methodology, and to determine the effect of extended exposure duration on survival. Plants were clonally propagated, then established and acclimated in growth chambers before exposure to a range of temperatures in a freeze chamber. 'Tifway' and 'TifSport' (-7.9°C) were significantly hardier than 'Princess' (-6.9°C), but less freeze tolerant than 'U-3' (-8.9°C), 'Patriot' (-9.7°C), and 'Midlawn' (-10.3°C). Riviera (-8.3°C) was significantly hardier than Princess, but less freeze tolerant than Patriot and Midlawn. In a second set of experiments, acclimated plants were held at constant, subfreezing temperatures for various periods of time in a refrigerated bath. Survival of U-3 and Riviera decreased to 25% or less when exposed to -7.0°C for 2 or 5 d, compared with 100 and 83% survival, respectively, when plants were removed from the bath immediately after equilibrating at -7.0°C. Princess exhibited 89% survival when removed immediately after equilibrating at -5.4°C, but survival after 2, 24, and 72 h was 67, 30, and 11%, respectively. Although minimum exposure temperature is a primary determinant of survival, freeze damage to turf bermudagrasses increased as exposure duration increased.
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Seashore paspalum (Paspalum vaginatum Sw.) is a warm-season turfgrass, best known for its superior salt tolerance. Plants are subject to injury during winter conditions along the northern boundary of their zone of adaptation. New cultivars that are more tolerant to low temperatures are needed for use in the transition zone. Cold tolerance has been correlated with the degree of unsaturation in membrane lipid fatty acids. Unsaturated fatty acids are thought to aid in maintaining membranes in a fluid state necessary for biological functioning (homeophasic adaptation). The primary objective was to characterize fatty acid composition of membrane lipids in three genotypes differing in cold tolerance. A second objective was to investigate changes in fatty acid content in these genotypes during exposure to low temperatures. Cold-treated plants were exposed to a 10-h photoperiod at 8°/4°C day/night temperatures and light intensity of 250 μmol m-2 s-1 photosynthetic photon flux density for 3 wk. Rhizomes and crowns were harvested at 7-d intervals. Total lipids were extracted and the polar lipids separated by thin-layer chromatography. Fatty acids were identified by gas chromatography (GC) and mass spectroscopy. In all three genotypes, the two saturated fatty acids, palmitic acid and stearic acid, did not change during cold treatment. The triunsaturated linolenic acid increased significantly during low temperature exposure. The magnitude of change was greater in the finer-textured and more cold-tolerant PI 509018-1 ('SeaIsle1') than in the intermediately cold-tolerant 'Adalayd' or in the cold-susceptible, coarse-textured PI 299042. These findings suggest that accumulation of linolenic acid partly explains the differential response in their cold tolerance.
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Information is lacking regarding the changes of endogenous soluble carbohydrates of saltgrass [Distichlis spicata (L.) Greene] during cold acclimation. The objective of this study was to quantify soluble carbohydrates and their relationships to freezing tolerance in six saltgrass accessions (A65, A29, C66, 32, 55, and 48). The study was performed at monthly intervals under natural acclimation in two consecutive winter seasons (October 1999-April 2000 and October 2000-April 2001) at Fort Collins, CO. Concurrent with LT 50 (subfreezing temperature resulting in 50% mortality) assessment, soluble carbohydrates, including sucrose, fructose, glucose, raffinose, and stachyose were measured by gas chromatography (GC). Results indicated significant differences among accessions and sampling dates in LT50 and carbohydrate content. Sucrose was the predominant sugar, but did not show a clear seasonal trend and had no correlation with freezing tolerance. Fructose, glucose, raffinose, and stachyose exhibited clear seasonal changes, reaching highest concentrations during midwinter. In December of both seasons, higher concentration of fructose and glucose were observed in 48 and 55 as compared with other accessions. Accession A29 had the highest concentration of raffinose in December and January in both seasons. A29 also had the highest stachyose content in midwinter of 1999-2000. Higher fructose, glucose, or raffinose concentrations were frequently observed in accessions of 48, 55, and A29, which coincided with their lower LT50 as compared with the other accessions. In contrast, C66 had the lowest sugar concentrations, which related to its sensitivity to low temperatures. These results indicate that fructose, glucose, raffinose, and stachyose may play important roles in saltgrass freezing tolerance.
Article
Bermudagrasses, Cynodon spp., periodically sustain winter injury in the transition zone between warm- and cool-season turfgrasses. Our objective was to determine relative freeze tolerance levels of advanced lines, recently released cultivars, and standard varieties by means of laboratory-based methodology. Freeze tolerance evaluations were divided into three groups on the basis of intended use. The vegetatively propagated fairway types (and their freeze tolerance values) included 'GN-1' (-5.9°C), 'Baby' (-6.7°C), 'Tifway' (-6.7°C), 'TifSport' (-7.2°C), 'Quickstand' (-8.0°C), and 'Midlawn'(-8.4°C). GN-1 was significantly less hardy than TifSport, Quickstand and Midlawn. The second set of bermudagrasses comprised the seed-propagated varieties: 'Arizona Common' (-5.6°C), 'Mirage' (-6.1°C), 'Jackpot' (-6.3°C), 'Guymon' (-7.4°C), and 'Yukon' (-7.6°C). Arizona Common was significantly less freeze tolerant than Guymon and Yukon. Mirage and Jackpot were not significanfiy hardier than Arizona Common. The third series of plants included vegetatively propagated bermudagrasses used for putting greens: 'Champion' (-4.8°C), 'Floradwarf' (-4.9°C), 'MS-Supreme' (-5.2°C), 'MiniVerde'(-5.8°C), 'Tifeagle' (-6.0°C), 'Tifdwarf' (-6.5°C), and 'Tifgreen' (-6.5°C). Tifdwarf and Tifgreen were significantly hardier than all of the other putting green bermudagrasses tested except for Tifeagle. Results should be useful in selecting appropriate genotypes for the transition zone of turfgrass adaptation.
Article
Roots of sour orange ( Citrus aurantium L.), ‘Carrizo’ citrange [ C. sinensis L. (Osbeck.) × Poncirus trifoliata L. (Raf.)] and ‘Swingle’ citrumelo [ C. paradisi Macf. × P. trifoliata L. (Raf.)] seedlings were exposed to various high temperatures for 20 minutes and heat injury was determined by electrolyte leakage procedures, microscopic examination, and visual observations. Temperatures at the midpoint of sigmoidal curves fitted through electrolyte leakage data for excised roots were 51.6° ± 0.5°C, 52.5° ± 0.7°, and 53.5° ± 0.5° for ‘Carrizo’ citrange, sour orange, and ‘Swingle’ citrumelo rootstocks, respectively. Electrolyte leakage results with excised roots were supported by microscopic examination and visual observations of whole plants.
Article
Rhizomes of 'Meyer' zoysiagrass (Zoysia japonica Steud.) were subjected to temperatures below 0 °C and were subsequently placed in a growth chamber with air at 34 °C day/28 °C night to determine the rate of shoot growth from nodes. Rhizomes exposed to subzero temperatures produced shoots steadily up to 16 days after freezing (DAF), but subsequent shoot growth from rhizomes was minimal. At 32 DAF, shoots were present on 68% and 44% of the nodes of unfrozen control (2 °C) rhizomes and those frozen to -7 °C, respectively. In another study, samples were frozen to a sublethal temperature (-7 °C) to examine the distribution of extracellular ice voids near the apical meristems of rhizomes and to characterize tissue recovery. Extracellular voids were present within the leaf tissue and between the leaves in samples prepared for scanning electron microscopy (SEM) immediately after freezing to -7 °C. By 12 DAF, most of the remaining voids were observed in older leaves. Nearly all extracellular voids in the leaves were absent by 20 DAF. However, by 28 DAF, some rhizomes still had small voids between leaves. Although the structure of zoysiagrass rhizomes subjected to -7 °C was temporarily disrupted, tissues recovered from extracellular freezing and new shoot growth was produced following exposure to warm temperatures.
Article
Stolons of `Raleigh', `Floratam', and FX-332 St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] were sampled from the field between October and March in two consecutive years to evaluate accuracy of an electrolyte leakage (EL) method for predicting freezing tolerance. Lethal temperatures of stolons estimated using EL were compared to those obtained by regrowth tests in the greenhouse. Mean lethal low temperatures for regrowth and EL methods over 12 sampling dates were `Floratam', –4.5C (regrowth) vs. –4.4C (EL); FX-332, –4.2C (regrowth) vs. –4.9C (EL); and `Raleigh', –6.0C (regrowth) vs. –5.4C (EL). A positive correlation (r = 0.81) was observed between EL-predicted and regrowth lethal temperatures for `Raleigh', which exhibited some acclimation during the first sampling year. The EL technique consistently predicted a lower lethal temperature for `Raleigh' than for `Floratam', which corroborates field observations concerning freezing tolerance of these two cultivars.
Article
Meyer' zoysiagrass (Zoysia japonica Steud.) has been the predominant cultivar used in the transition zone since its release in 1952 because of its excellent freezing tolerance and good turf quality. However, it is relatively slow to establish and coarser in texture than cultivars of Z.matrella. Researchers at Texas A & M released several zoysiagrass cultivars including 'Crowne', 'Cavalier', 'Diamond', and 'Palisades' that exhibited higher turf quality than 'Meyer' in southern evaluations, but they lacked freezing tolerance necessary in the transition zone. Our goal is to evaluate field performance of 381 zoysiagrass progeny resulting from crosses between freezing-tolerant cultivars and high quality lines which may have desirable characteristics lacking in 'Meyer', but with a comparable level of freezing tolerance. Eventually, this may lead to the selection of one or more high quality cultivars that are well adapted to the transition zone environment.
Article
Development of drought resistant, water-conserving cultivars continues to be an objective of turfgrass breeding programs. This study was conducted to determine for 15 zoysiagrasses [Zoysia japonica Steud., Z. matrella (L.) Merr., and Z. japonica Steud. x Z. tenuifolia Willd.] under greenhouse conditions (i) water relations characteristics, (ii) survival and recovery from extreme water stress, and (iii) the relationship of water relations characteristics to supplemental irrigation requirement determined in field studies. Leaf water potential at zero turgor (Ψ L0 ) ranged from -1.76 MPa to -2.52 MPa before, and from -2.18 MPa to -2.59 MPa after water stress. Though Ψ L0 of genotypes such as Cavalier, El Toro, and Emerald decreased after stress, Ψ L0 of genotypes such as Korean Common and DALZ85t5 did not change. Osmotic potential at full turgor (Ψ π100 ) of genotypes such as DALZ8501 and DALZ8506 was similar or increased after water stress but decreased for genotypes such as Crowne and Korean Common. The Ψ L0 and Ψ π100 after stress were negatively correlated with recovery from stress and positively correlated with irrigation requirement. Zoysia genotypes with low relative water content at zero turgor (RWC 0 ), bulk modulus of tissue elasticity (E), and apoplastic water fraction (β) demonstrated poor recovery from stress and required more supplemental irrigation. Cultivars such as Crowne, El Toro, and Palisades had the greatest recovery from stress, the least irrigation requirement, more negative Ψ L0 and Ψ π100 , and positive RWC 0 , e, and β. This study demonstrates that improvements in biophysical as well as morphological traits should contribute to development of water-conserving Zoysiagrass germplasm.
Article
'Midiron' and 'U3' bermudagrass were exposed to conditions known to induce cold acclimation [e.g., 8/4°C (day/night) temperature, 10-h photoperiod, 250 μmol m-2 s-1 photosynthetic photon flux density (PPFD)]. Tissues (leaves, crowns, and roots) were harvested and stored frozen until processed. Polar membrane lipids were isolated by thin layer chromatography, and fatty acids (FA) were separated and quantified by gas chromatography. Different organs from the same plant responded differentially to low temperature. Crowns showed the most dramatic changes in total FA content and composition and were the focus of this study. Overall, greater than 95% of the total FA content was accounted for by four FA species: palmitic acid (16:0), stearic acid (18:0), linoleic acid (18:2), and linolenic acid (18:3). Midiron (relatively cold-tolerant) responded more rapidly and to a greater extent than did U3 (relatively cold-sensitive) as illustrated by the nearly four-fold increase of unsaturated FA:saturated FA ratio for Midiron vs. U3, and by the significant difference between the double bond index of the two genotypes. These data suggest that specific desaturase enzymes (e.g., ω-3 and ω-6) are of fundamental importance in controlling membrane lipid/fatty acid composition in response to low temperature and ultimately in avoiding the winter damage suffered by bermudagrass along its northern boundary of adaptation.
Article
The winter hardiness of alfalfa cultivars (Medicago sativa L.) affects stand persistence in northern climates. Fall growth, a measure of fall dormancy, has been associated with alfalfa winter hardiness in some areas of North America, including Minnesota. This study evaluated 251 North American alfalfa cultivars for fall growth and winter injury and determined the relationship between fall growth and winter injury scores under Minnesota winter conditions. All cultivars were established by transplanting 9-wk-old plants into space-planted field plots in June 1991, 1992, and 1993. Plants were clipped in mid July and early September each yr and overwintered in the field. Fall growth was measured as individual plant height in mid-October 1992 and 1993. Winter injury was evaluated in May each year. Entries differed for fall growth and winter injury score in all years. The 2-yr-mean fall growth score was related to the 3-yr-mean winter injury score (r2 = 0.85). Only seven of 251 entries fell outside the 95% confidence interval of the linear regression of winter injury score on fall growth score. Fall growth scores from 1992 and 1993 were correlated (r2 = 0.88). Winter injury scores from 1992, 1993, and 1994 were also correlated (r2 = 0.69-0.96). Although concerns exist about the use of fall growth score to predict winter hardiness in less severe climates, it remains a useful predictor of alfalfa winter hardiness in Minnesota when winter injury data are not available.
Article
Sodium dodecylsulfate (SDS) polyacrylamide gel electrophoresis (PAGE) and fluorography of in vivo radiolabeled proteins has revealed that protein synthesis in crowns of 'Midiron' and Tifgreen' bermudagrasses (Cynodon dactylon L. Pers. x C. transvaalensis Burtt-Davy) is altered in association with cold acclimation (CA). Increased synthesis of some proteins in association with CA in Midiron crowns correlates with the greater freezing tolerance of Midiron compared with Tifgreen. This study was undertaken to (i) characterize further alterations in protein synthesis in Midiron and Tifgreen crowns utilizing analytical isoelectric focusing (IEF)/SDS-PAGE [two-dimensional (2D-) PAGE], and (ii) identify cold-regulated (COR) proteins, proteins encoded by genes persistently upregulated during CA, through sequence analysis of peptides recovered after micropreparative 2D-PAGE and protease digestion. Plants were grown for 26 d in controlled-environment chambers under acclimating [8/2°C (day/night) cycles with 10 h photoperiods] or nonacclimating [28/24°C] conditions. Proteins synthesized by isolated crowns were radiolabeled in vivo for 16 h with 355-methionine and 35 S-cysteine. Among several groups of COR proteins synthesized in Midiron and Tifgreen crowns, low molecular weight (about 20-28 kilodalton) basic (LB) COR proteins were synthesized in greater amounts and numbers in Midiron than Tifgreen crowns. Among the LB COR proteins, a 27-kD basic COR protein was synthesized prominently in crowns of both Midiron and Tifgreen plants. This protein from Midiron crowns was designated COR27 and identified as a chitinase (E.C. 3.2.1.14) through protein sequencing.
Article
There are few reports on cold hardening in warmseason turfgrass species. The purpose of our study was to measure changes in cold hardiness and carbohydrate composition of Zoysia japonica Steud ‘Meyer’ turfgrass during fall and winter. Both rhizome and stolon tissue developed comparable levels of cold hardiness as measured by an artificial freeze test. A significant (P <; 0.05) reduction in percentage survival of tissue occurred at freeze-test temperatures at or below −6.7 C on September 23 and Octobei 26; and −10.0, −8.9, and −12.8 C on November 30. January 10, and March 13, respectively. Total nonstructural carbohydrate (TNC) concentration of both rhizome and stolon tissue increased during September, remained relatively constant near 50% of dry weight until December, and was reduced to about 15% by March 15. Starch comprised the largest percentage of the carbohydrate fractions and closely followed TNC concentration. Total sugars increased slightly during fall, while reducing sugars remained nearly constant during the entire sampling period. Please view the pdf by using the Full Text (PDF) link under 'View' to the left. Copyright © . .
Article
Although zoysiagrasses (Zoysia japonica Steud., Z. matrella (L.) Merr, and Z. tenuifolia Willd.) provide an excellent golf course fairway or tee surface, their use in areas of intense play may be limited because of their relatively slow recuperative potential. The objective of the following research was to identify zoysiagrass varieties with improved recuperative potential that may be adapted to such situations. Divot injury was simulated in 2003 and 2004 on 24 zoysiagrass varieties maintained under golf course fairway conditions. A digital image of each divot was collected on the day of injury and regularly thereafter until full recovery was reached. Divot images were analyzed for percent green turf cover using digital image analysis to quantify recovery percentages. In both years, 'Crown,' 'Palisades,' and 'Zorro' were among the fastest varieties to recover from injury. 'El Toro' had very rapid recovery in 2003, but not in 2004. 'Meyer' and 'Emerald' were consistently the slowest to recover from injury. Please view the pdf by using the Full Text (PDF) link under 'View' to the left. Copyright © 2005. . © 2005 Plant Management Network.
Article
Poor winter survival often limits the successful persistence of perennial Pennisetum species to the warmest areas of the southern United States. To investigate winter survival in Pennisetum, conductance measurements were used to evaluate changes in electrolyte leakage as an indicator of freezing tolerance of selected species using field-grown plants, growth chamber-grown seedlings, and callus tissue. A buffelgrass (Pennisetum ciliare [L.] Link syn Cenchrus ciliaris L.) x birdwoodgrass (C. setigerus L.) hybrid (B x BW) with poor winter survival at College Station, Texas, a moderately winter-hardy buffelgrass genotype (PI 409704), and a winter-hardy species (P. orientale L. C. Rich. cv. Cowboy) were tested in the field in 1989-1990. Tiller bases were collected in December, January, March, and April, with the freezing tolerance estimated by the electrolyte leakage method. The freeze tolerance of PI 409704 in December was similar to Cowboy and significantly greater than B x BW, however, only Cowboy survived the 1989-1990 winter in the field. Seedlings of two winter-hardy species, Cowboy and P. flaccidum Griseb. cv. Carostan, two moderately winter-hardy species P. mezianum Leeke, PI 214061 and PI 409704, and a buffelgrass cultivar with poor winter hardiness (Common) were grown at either 20 degrees/15 degrees C or 10 degrees/5 degrees C with photoperiods of 9 h or 15 h. The freezing tolerance was estimated by the electrolyte leakage method. Photoperiod had no effect on the freezing tolerance of any genotype tested. All species had greater freezing tolerance when grown at 10 degrees/5 degrees C with Carostan having the greatest freezing tolerance (-8.3 degrees C) and Common the least (-4.0 degrees C). Callus tissues from the same genotypes were grown at either 17 degrees C or 7 degrees C, and the freezing tolerance determined. Carostan calli had greater freezing tolerance at 7 degrees C (-3.6 degrees C) than at 17 degrees (-1.1 degrees C). The other genotypes exhibited no detectable freezing tolerance at either temperature. These results indicate that freezing tolerance in Carostan and Cowboy may be an important factor in their winter survival.
Article
Accurate cover estimates in turfgrass research plots are often difficult to obtain because of the time involved with traditional sampling and evaluation techniques. Subjective ratings are commonly used to estimate turfgrass cover, but the data can be quite variable and difficult to reproduce. New technologies and software related to digital image analysis (DIA) may provide an alternative method to measure turfgrass parameters more accurately and efficiently than current techniques. A series of studies was conducted to determine the applicability of DIA for turfgrass cover estimates. In the first study, plots containing a range (1-16) of bermudagrass [Cynodon dactylon (L.) Pers.] plugs of specific diameter (15.0 cm) were established to represent values of turfgrass cover from 0.75 to 12%, by 0.75% increments. Digital images (1280 by 960 pixels) were taken with a digital camera and processed for percent green color to a software package. Estimates of green turfgrass cover by DIA were highly correlated (r2 > 0.99) to the calculated values of tudgrass cover. In a second study, DIA of turfgrass cover was compared by subjective analysis (SA) and line-intersect analysis (LIA) methods for estimating cover in eight plots of zoysiagrass (Zoysia japonica Steudel). The mean variance of percent cover determined by DIA (0.65) was significantly lower than SA (99.12) or LIA (13.18). Digital image analysis proved to be an effective means of determining turfgrass cover, producing both accurate and reproducible data. In addition, the technique effectively removes the inherent error and evaluator bias commonly associated with subjective ratings.
Article
The plant survival of three ecotypes of seashore paspalum (Paspalum vaginatum Swartz) submitted to freezing temperatures was evaluated by two methods: electrolyte leakage and freeze shock-recovery. Bermudagrass [Cynodon dactylon (L.) Pets. cv. Midiron] was used as a check. Acclimated and nonacclimated plants were evaluated from 1994 to 1995 in Georgia by both methods to compare their performance. Results indicated that seashore paspalum was slower to acclimate than Midiron bermuda under the treatment conditions used in this experiment. However, a significant acclimation effect was found in HI-1 paspalum, indicating the presence of variability for this trait within the species. The LT50 determinations demonstrated the superior cold hardiness of Midiron compared with seashore paspalum. Among the paspalum ecotypes, HI-1 ranked superior to Adalayd and PI 299042, respectively, when plants were acclimated (AC). When nonacclimated (NA), Adalayd ranked superior to the other two ecotypes. These genotypic rankings were consistent for both methods of evaluation, indicating their effectiveness for efficiently screening cold hardiness responses among multiple ecotypes. Electrolyte leakage curves indicated that the lethal electrolyte leakage levels for AC and NA paspalum ecotypes were similar. Additional studies are required to evaluate the mechanism present in HI-1, which showed significant acclimation effects on plant survival.
Article
Little is known about environmental and physiological factors affecting centipedegrass [Eremochloa ophiuroides (Munro) Hackel] winter survival. Stolons of common and 'Oklawn' centipedegrass were sampled from field- or growth chamber-grown turf in three separate experiments to (i) determine freezing tolerance of acclimated and non-acclimated turf; (ii) identify and quantify nonstructural carbohydrates (NSC) in acclimated and nonacclimated turf, and (iii) relate NSC levels to freezing tolerance. Lethal temperatures for common and Oklawn were similar throughout all studies [...]
Article
Two rhododendron cultivars, ‘Pohjola's Daughter’ and ‘Helsinki University’, were grown at +15 and +24°C, each combined with a photoperiod of 14 h (short day, SD) or 20 h (long day, LD). After a 112-day growing season, they were subjected to a hardening regime of fortnightly decreasing temperature (+9, +5, +1 and −2°C) and a 12-h photoperiod, except that part of the plants grown in LD had LD also at +9 and +5°C. At −2°C, all plants were in darkness. Controlled freezing tests of the leaves were performed before each change in temperature. The injury was evaluated visually and by electrolyte leakage (EL) tests. The observations on the visual assessment were analysed with logit models, and the EL data with non-linear sigmoid functions. The visually scored 50% damage (VD50) correlated better with the EL tests than 10 or 90% damage. Photoperiod and temperature during the growing season affected the cold hardiness of both cultivars, but they differed in their responses. ‘Pohjola's Daughter’ benefited from SD as well as from high temperature, while ‘Helsinki University’ attained better hardiness at a cool growing season temperature and was less sensitive to photoperiod.
Article
Thesis (Ph. D.)--Texas A & M University, 2000. Includes bibliographical references (leaves 209-216). Photocopy.
Article
Genetic variations among 17 accessions of zoysiagrasses collected from natural populations in Japan were investigated by RFLP analyses of chloroplast DNA (cpDNA) and nuclear DNA. These accessions were classified into five species based on morphological characteristics: Zoysia japonica, Z. matrella, Z. tenuifolia, Z. sinica, and Z. macrostachya. On the basis of eight kinds of RFLPs in cpDNAs detected across accessions, six chloroplast genome types (types A-F) were identified. Although type-A cpDNA was shared by five accessions of japonica and four accessions of matrella, derivative cpDNAs of type A, which each arose by a mutation, were identified in one accession of japonica (type B) and in two accessions of matrella (type C). One accession of japonica which showed spikelets similar to those of shapes macrostachya, contained type-F cpDNA as did sinica and macrostachya. The two accessions of tenuifolia each showed a specific cpDNA type, i.e. types D and E. Genetic relationships among the 17 accessions were investigated by the RFLP analyses of nuclear DNA with 20 genomic and gene probes. A dendrogram constructed with genetic distances calculated from the RFLP patterns indicated four major groups among them. Six accessions of japonica comprised one group, whereas the one accession of japonica possessing the type-F cpDNA was clustered with macrostachya and sinica. Four accessions of matrella with type A cpDNA constituted another group in the dendrogram, showing a closer relationship to the japonica accessions than to the other two accessions of matrella. The remaining two accessions of matrella and tenuifolia accessions were grouped together. These data indicate that zoysiagrasses distributed in Japan harbor highly genetic variations, and that interspecific hybridization has occurred in natural populations.
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